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Electronic compressibility of magic angle graphene superlatticesMar 25 2019We report the first electronic compressibility measurements of magic angle twisted bilayer graphene. The evolution of the compressibility with carrier density offers insights into the interaction-driven ground state that have not been accessible in prior ... More

Strain Modulated Superlattices in GrapheneMar 25 2019The quest to create material systems with novel electronic states has led in many cases to the investigation of interfaces. The potential of merging different 2D materials via vertical or horizontal stacking to create van der Waals or lateral heterostructures ... More

On the interplay of paramagnetism and topology in the Fe-based High Tc SuperconductorsMar 25 2019The high Tc superconductor FeTe0.55Se0.45 has recently been shown to support a surface state with topological character. Here we use low-energy laser-based ARPES with variable light polarization, including both linear and circular polarization, to re-examine ... More

A Bayesian analysis of neutron spin echo data on polymer coated gold nanoparticles in aqueous solutionsMar 25 2019We present a neutron spin echo study (NSE) of the nanosecond dynamics of polyethylene glycol (PEG) functionalised nanosized gold particles dissolved in D$_2$O at two temperatures and two different PEG molecular weights. The analysis of the NSE data was ... More

On the role of the electron-phonon interaction in the temperature dependence of the gap of lead halide perovskitesMar 25 2019Lead halide perovskites are causing a change of paradigm in photovoltaics. Among other peculiarities, these perovskites exhibit an atypical temperature dependence of the fundamental optical gap: It decreases in energy with decreasing temperature. So far ... More

Designing a path towards superconductivity through magnetic exchange in transition-metal intercalated bilayer grapheneMar 25 2019This study examines the potential of superconductivity in transition metal (TM) intercalated bilayer graphene through a systematic study of the electronic and magnetic properties. We determine the electronic structure for all first row TM elements in ... More

DFT Calculations of Temperature-Dependent NQR Parameters in α-paradichlorobenzene and β-HMXMar 25 2019A method for first principles predictions of observed temperature-dependent NQR spectra is presented using density functional theory (DFT) and the isobaric T-dependent NQR frequencies of 35Cl and 14N nuclei are computed for the two molecular crystals ... More

Feedback-Induced Quantum Phase Transitions Using Weak MeasurementsMar 25 2019We show that applying feedback and weak measurements to a quantum system induces phase transitions beyond the dissipative ones. Feedback enables controlling essentially quantum properties of the transition, i.e., its critical exponent, as it is driven ... More

Bridging the Gap: 3D Real-Space Characterization of Colloidal Assemblies via FIB-SEM TomographyMar 24 2019Insight in the structure of nanoparticle assemblies up to a single particle level is key to understand the collective properties of these assemblies, which critically depend on the individual particle positions and orientations. However, the characterization ... More

Determinant Quantum Monte Carlo Study of Exhaustion in the Periodic Anderson ModelMar 24 2019The Kondo and Periodic Anderson models describe many of the qualitative features of local moments coupled to a conduction band, and thereby the physics of materials such as the heavy fermions. In particular, when the exchange coupling $J$ or hybridization ... More

Probing the Melting of a Two-dimensional Quantum Wigner Crystal via its Screening EfficiencyMar 24 2019One of the most fundamental and yet elusive collective phases of an interacting electron system is the quantum Wigner crystal (WC), an ordered array of electrons expected to form when the electrons' Coulomb repulsion energy eclipses their kinetic (Fermi) ... More

Kolmogorov-Crespi Potential For Multilayer Transition Metal Dichalcogenides: Capturing Structural Transformations In Moiré SuperlatticesMar 24 2019We develop parameters for the interlayer Kolmogorov-Crespi (KC) potential to study structural features of four transition metal dichalcogenides (TMDs): MoS$_2$, WS$_2$, MoSe$_2$ and WSe$_2$. We also propose a mixing rule to extend the parameters to their ... More

Ultrafast decoupling of atomic sublattices in a charge-density-wave materialMar 24 2019Atomic rearrangements within crystals lie at the foundation of electron-phonon-coupled phenomena such as metal-insulator transition and superconductivity. Advanced laser-pump-probe studies have recently focused on various charge-density-wave (CDW) materials ... More

Tunable magnetism of hexagonal Anderson droplet on the triangular latticeMar 22 2019Motivated by recent progress on quantum engineered Kondo lattices, we numerically investigated the local magnetic properties of a hexagonal Anderson impurity droplet consisting of multiple rings of magnetic atoms periodically arrayed on a triangular lattice. ... More

Broadband Phonon Scattering in PbTe-based Materials Driven Near the Ferroelectric Phase Transition by Strain or AlloyingMar 22 2019The major obstacle in the design of materials with low lattice thermal conductivity is the difficulty in efficiently scattering phonons across the entire frequency spectrum. Using first principles calculations, we show that driving PbTe materials to the ... More

Electrical suppression of spin relaxation in GaAs(111)B Quantum WellsMar 22 2019Spin dephasing via the spin-orbit interaction (SOI) is a major mechanism limiting the electron spin lifetime in III-V zincblende quantum wells. The dephasing can be suppressed in GaAs(111) quantum wells by applying an electric field. The suppression has ... More

Magnon-polaritons in dysprosium ferriteMar 22 2019Magnon-photon coupling at THz frequencies is demonstrated in the antiferromagnet dysprosium ferrite (DyFeO3). Transmission though polycrystaline samples of different thicknesses was studied at frequencies of 0.2-0.35~THz and temperatures ranging from ... More

Active Materials: Biological Benchmarks and Transport LimitationsMar 22 2019These lecture notes were prepared for the 2018 Summer School on `Active Matter and Non-equilibrium Statistical Physics' at l'\'{E}cole de Physique des Houches. They survey metabolic activity across a wide range of living organisms, and consider size limitations ... More

Direct Observation of a Uniaxial Stress-driven Lifshitz Transition in Sr$_{2}$RuO$_{4}$Mar 22 2019Pressure represents a clean tuning parameter for traversing the complex phase diagrams of interacting electron systems and as such has proved of key importance in the study of quantum materials. Application of controlled uniaxial pressure has recently ... More

Rearrangement of uncorrelated valence bonds evidenced by low-energy spin excitations in YbMgGaO4Mar 22 2019DC-magnetization data measured down to 40 mK speak against conventional freezing and reinstate YbMgGaO$_4$ as a triangular spin-liquid candidate. Magnetic susceptibility measured parallel and perpendicular to the $c$-axis reaches constant values below ... More

Stationary Charge Imbalance Effect in System of Coupled Josephson JunctionMar 22 2019We investigate stationary charge imbalance effect in the system of coupled overdamped Josephson junctions. We show that coupling between junction and nonzero stationary charge imbalance in the resistive state bring to a decrease of the Josephson frequency ... More

Controlling exciton dynamics in two-dimensional MoS2 on hyperbolic metamaterial-based nanophotonic platformMar 22 2019The discovery of two-dimensional transition metal dichalcogenides (2D TMDs) has promised next-generation photonics and optoelectronics applications, particularly in the realm of nanophotonics. Arguably, the most crucial fundamental processes in these ... More

Deep learning as closure for irreversible processes: A data-driven generalized Langevin equationMar 22 2019The ultimate goal of physics is finding a unique equation capable of describing the evolution of any observable quantity in a self-consistent way. Within the field of statistical physics, such an equation is known as the generalized Langevin equation ... More

Localization in steady states of microcavity polaritonsMar 22 2019The nature of non-equilibrium steady state formation in driven-dissipative systems is a fundamental open question in modern physics. In the case of isolated systems, thermodynamics foresees that all evolutions lead to an equilibrium state. However, this ... More

Bulk-Free Topological Insulator Bi2Se3 nanoribbons with Magnetotransport Signatures of Dirac Surface StatesMar 22 2019Many applications for topological insulators (TIs) as well as new phenomena require devices with reduced dimensions. While much progress has been made to realize thin films of TIs with low bulk carrier density, nanostructures have not yet been reported ... More

Order and Disorder in the Magnetisation of the Chiral Crystal CrNb$_3$S$_6$Mar 22 2019Competing magnetic anisotropies in chiral crystals with Dzyaloshinskii Moriya exchange interactions can give rise to non-trivial chiral topological magnetisation configurations with new and interesting properties. One such configuration is the magnetic ... More

Many-Body Effective Energy Theory: photoemission at strong correlationMar 22 2019In this work we explore the performance of a recently derived many-body effective energy theory for the calculation of photoemission spectra in the regime of strong electron correlation. We apply the theory to paramagnetic MnO, FeO, CoO, and NiO, which ... More

Mean squared displacement in a generalized Lévy walk modelMar 22 2019L\'evy walks represent a class of stochastic models (space-time coupled continuous time random walks) with applications ranging from the laser cooling to the description of animal motion. The initial model was intended for the description of turbulent ... More

Learning magnetization dynamicsMar 22 2019Deep neural networks are used to model the magnetization dynamics in magnetic thin film elements. The magnetic states of a thin film element can be represented in a low dimensional space. With convolutional autoencoders a compression ratio of 1024:1 was ... More

Quantum criticality of granular SYK matterMar 22 2019We consider granular quantum matter defined by Sachdev-Ye-Kitaev (SYK) dots coupled via random one-body hopping. Within the framework of Schwarzian field theory, we identify a zero temperature quantum phase transition between an insulating phase at weak ... More

Collapse of orthotropic spherical shellsMar 22 2019We report on the buckling and subsequent collapse of orthotropic elastic spherical shells under volume and pressure control. Going far beyond what is known for isotropic shells, a rich morphological phase space with three distinct regimes emerges upon ... More

Insights from Molecular Dynamics Simulations on Structural Organization and Diffusive Dynamics of an Ionic Liquid at Solid and Vacuum InterfacesMar 22 2019Hypothesis A prototypical modelling approach is required for a full characterisation of the static and equilibrium dynamical properties of confined ionic liquids (ILs), in order to gain predictive power of properties that are difficult to extract from ... More

Low temperature specific heat of the 12442-type KCa_2Fe_4As_4F_2 single crystalsMar 22 2019Low-temperature specific heat (SH) is measured on the 12442-type KCa_2Fe_4As_4F_2 single crystal under different magnetic fields. A clear SH jump with the height \Delta C/T|_{T_c} = 130 mJ/mol K^2 was observed at the superconducting transition temperature ... More

A doubly associated reference perturbation theory for waterMar 22 2019In this work we develop a new classical perturbation theory for water which incorporates the transition to tetrahedral symmetry in both the dispersion and hydrogen bonding contributions to the free energy. This transition is calculated self-consistently ... More

Mathematical open problems in Projected Entangled Pair StatesMar 22 2019Projected Entangled Pair States (PEPS) are used in practice as an efficient parametrization of the set of ground states of quantum many body systems. The aim of this paper is to present, for a broad mathematical audience, some mathematical questions about ... More

Elastic Compliance and Stiffness Matrix of the FCC Lennard-Jones Thin Films: Influence of Thickness and TemperatureMar 22 2019The fcc Lennard-Jones crystal is used as a generic model of solid to study the elastic properties of thin films as a function of thickness and temperature. The Monte Carlo algorithm is used to calculate the average deformations along the axes in the isostress-isothermal ... More

Ultra-sensitive SQUID instrumentation for MEG and NCI by ULF MRIMar 22 2019The requirements for the construction of ultra-sensitive SQUID instrumentation as used in biomagnetism are presented. Typically, SQUIDs are inductively coupled to pick-up coils and for this arrangement one can improve the noise performance by increasing ... More

Al$_{5+α}$Si$_{5+δ}$N$_{12}$, a new Nitride compoundMar 22 2019We report on the synthesis of new nitride-based compound by using annealing of AlN heteroepitaxial layers under a Si-atmosphere at temperatures between 1350$^\circ$C and 1550$^\circ$C. The structure and stoichiometry of this compound are investigated ... More

Role of remote interfacial phonons in the resistivity of grapheneMar 22 2019The temperature ($\it T$) dependence of electrical resistivity in graphene has been experimentally investigated between 10 and 400 K for samples prepared on various substrates; HfO$_2$, SiO$_2$ and h-BN. The resistivity of graphene shows a linear $\it ... More

Bayesian optimization of chemical composition: a comprehensive framework and its application to $R$Fe$_{12}$-type magnet compoundsMar 22 2019We propose a framework for optimization of the chemical composition of multinary compounds with the aid of machine learning. The scheme is based on first-principles calculation using the Korringa-Kohn-Rostoker method and the coherent potential approximation ... More

Investigation of Superconducting Gap Structure in HfIrSi using muon spin relaxation/rotationMar 22 2019Appearance of strong spin-orbit coupling (SOC) is apparent in ternary equiatomic compounds with 5$d$-electrons due to the large atomic radii of transition metals. SOC plays a significant role in the emergence of unconventional superconductivity. Here ... More

Dip-coating of suspensionsMar 22 2019Withdrawing a plate from a suspension leads to the entrainment of a coating layer of fluid and particles on the solid surface. In this article, we study the Landau-Levich problem in the case of a suspension of non-Brownian particles at moderate volume ... More

Giant Dzyaloshinskii-Moriya interaction (DMI) in magnetic bilayers and its microscopic originMar 22 2019Skyrmions are widely regarded as promising candidates for emergent spintronic devices. Large Dzyaloshinskii-Moriya interaction (DMI) is critical to the realization of functional skyrmion technology. Here we present a comprehensive, first principles study ... More

Large g factor in bilayer WS$_2$ flakesMar 22 2019The valley of transition metal dichalcogenides provides an additional platform to manipulate spin due to its unique selection rule. Normally, intralayer optical transitions in magnetic field show a Zeeman splitting with g factor of about $-4$. Here we ... More

Fragmented Electronic Spins with Quantum Fluctuations in Organic Mott Insulators near Quantum Spin LiquidMar 22 2019Magnetic structures of organic Mott insulators X[Pd(dmit)2]2 (X=Me4P, Me4Sb), of which electronic states are located near quantum spin liquid (X=EtMe3Sb), are demonstrated by 13C NMR. Antiferromagnetic spectra and nuclear relaxations show two distinct ... More

Hot Carrier and Surface Recombination Dynamics in Layered InSe CrystalsMar 22 2019Layered indium selenide (InSe) is a van der Waals solid that has emerged as a promising material for high-performance ultrathin solar cells. The optoelectronic parameters that are critical to photoconversion efficiencies, such as hot carrier lifetime ... More

Spatiotemporal Mapping of Photocurrent in a Monolayer Semiconductor Using a Diamond Quantum SensorMar 22 2019The detection of photocurrents is central to understanding and harnessing the interaction of light with matter. Although widely used, transport-based detection averages over spatial distributions and can suffer from low photocarrier collection efficiency. ... More

Quantum Spin Ice Dynamics in the Dipole-Octupole Pyrochlore Magnet Ce$_2$Zr$_2$O$_7$Mar 21 2019Neutron scattering measurements on the pyrochlore magnet Ce$_2$Zr$_2$O$_7$ reveal an unusual crystal field splitting of its lowest $J$=5/2 multiplet, such that its ground state doublet is composed of m$_J$=$\pm$3/2, giving these doublets a dipole - octupole ... More

Consensus and diversity in multi-state noisy voter modelsMar 21 2019We study a variant of the voter model with multiple opinions; individuals can imitate each other and also change their opinion randomly in mutation events. We focus on the case of a population with all-to-all interaction. A noise-driven transition between ... More

Timescales in the quench dynamics of many-body quantum systems: Participation ratio vs out-of-time ordered correlatorMar 21 2019We study quench dynamics in the many-body Hilbert space using two isolated systems with a finite number of interacting particles: a paradigmatic model of randomly interacting bosons and a dynamical (clean) model of interacting spins-$1/2$. For both systems ... More

Emergent topology and symmetry-breaking order in correlated quench dynamicsMar 21 2019Quenching a quantum system involves three basic ingredients: the initial phase, the post-quench target phase, and the non-equilibrium dynamics which carries the information of the former two. Here we propose to identify both the topology and symmetry-breaking ... More

A Theoretical Investigation of Charge Density Wave Instability in CuS$_2$Mar 21 2019The existence of a charge density wave (CDW) in transition metal dichalcogenide CuS$_2$ has remained undetermined since its first experimental synthesis nearly 50 years ago. Despite conflicting experimental literature regarding its low temperature structure, ... More

Modeling meso-scale energy localization in shocked HMX, Part II: training machine-learned surrogate models for void shape and void-void interaction effectsMar 21 2019Mar 22 2019Surrogate models for hotspot ignition and growth rates were presented in Part I, where the hotspots were formed by the collapse of single cylindrical voids. Such isolated cylindrical voids are idealizations of the void morphology in real meso-structures. ... More

Non-Abelian Majorana fermions in topological $s$-wave Fermi superfluidsMar 21 2019By solving the Bogoliubov-De Gennes equations analytically, we derive the fermionic zero-modes satisfying the Majorana property that exist in vortices of a two-dimensional $s$-wave Fermi superfluid with spin-orbit coupling and Zeeman spin-splitting. We ... More

Quantitative magneto-optical imaging with ferrite garnetsMar 21 2019Magneto-optical imaging is a powerful technique for studying qualitative features of magnetic flux distributions in superconductors and other magnetic samples. However, magneto-optical imaging does not automatically return two-dimensional maps with the ... More

Influence of cap weight on the motion of a Janus particle very near a wallMar 21 2019The dynamics of anisotropic nano- to microscale colloidal particles in confined environments, either near neighboring particles or boundaries, is relevant to a wide range of applications. We utilized Brownian dynamics simulations to predict the translational ... More

Front-mediated melting of ultrastable glassesMar 21 2019Ultrastable vapor-deposited glasses display peculiar properties. In particular, upon heating they melt via a liquid front that originates at the free surface and propagates over a mesoscopic crossover length, before crossing over to bulk melting. We combine ... More

A Turing instability in the solid state: void lattices in irradiated metalsMar 21 2019Turing (or double-diffusive) instabilities describe pattern formation in reaction-diffusion systems, and were proposed in 1952 as a potential mechanism behind pattern formation in nature, such as leopard spots and zebra stripes. Because the mechanism ... More

Scanning Probe State Recognition With Multi-Class Neural Network EnsemblesMar 21 2019One of the largest obstacles facing scanning probe microscopy is the constant need to correct flaws in the scanning probe in situ. This is currently a manual, time-consuming process that would benefit greatly from automation. Here we introduce a convolutional ... More

How the overlap of excluded volume determines the configurational energy landscape and "thermodynamics" in the "one to five hard disks in a box" systemMar 21 2019In this work, the effects of excluded volume are studied in the "one to five hard disks in a box" system. For one and two disks in different types of cages, the attractive and repulsive forces are calculated analytically. Attractive forces are due to ... More

Strong pinning theory of thermal vortex creep in type II superconductorsMar 21 2019We study thermal effects on pinning and creep in type-II superconductors where vortices interact with a low density $n_p$ of strong point-like defects with pinning energy $e_p$ and extension $\xi$, the vortex core size. Defects are classified as strong ... More

Large enhancement of conductivity in Weyl semimetals with tilted cones: pseudo-relativity and linear responseMar 21 2019We study the conductivity of two-dimensional graphene-type materials with tilted cones as well as their three-dimensional Weyl counterparts and show that a covariant quantum Boltzmann equation is capable of providing an accurate description of these materials' ... More

Electronic states of (InGa)(AsSb)/GaAs/GaP quantum dotsMar 21 2019Detailed theoretical studies of the electronic structure of (InGa)(AsSb)/GaAs/GaP quantum dots are presented. This system is unique since it exhibits concurrently direct and indirect transitions both in real and momentum space and is attractive for applications ... More

Self-stabilizing laser sails based on optical metasurfacesMar 21 2019This article investigates the stability of 'laser sail'-style spacecraft constructed from dielectric metasurfaces with areal densities $<$1g/m$^2$. We show that the microscopic optical forces exerted on a metasurface by a high power laser (100 GW) can ... More

Revealing charge-tunneling processes between a quantum dot and a superconducting island through gate sensingMar 21 2019We report the detection and identification of charge-tunneling processes between a quantum dot and a superconducting island through radio-frequency gate sensing. We are able to resolve spin-dependent quasiparticle tunneling as well as two-particle tunneling ... More

Proving the curvature-induced frequency asymmetry of spin-wave modes in magnetic nanotubes with coplanar wave guidesMar 21 2019We calculate the optimal conditions to quantify curvature-induced nonreciprocity in the dispersion relation of a magnetic nanotube by calculating the coupling impedance between spin waves modes of the nanotube and Coplanar Wave Guides (CPWs). We calculate ... More

Study of Electron-Vibrational Interaction in Molecular Aggregates Using Mean-Field Theory: From Exciton Absorption and Luminescence to Exciton-Polariton Dispersion in NanofibersMar 21 2019We have developed a model in order to account for electron-vibrational effects on absorption, luminescence of molecular aggregates and exciton-polaritons in nanofibers. The model generalizes the mean-field electron-vibrational theory developed by us earlier ... More

Thermodynamic limit of the two-spinon form factors for the zero field XXX chainMar 21 2019In this paper we propose a method based on the algebraic Bethe ansatz leading to explicit results for the form factors of quantum spin chains in the thermodynamic limit. Starting from the determinant representations we retrieve in particular the formula ... More

Direct observation of a flat band and a partially filled interlayer band in a Cs/graphene/Cs trilayerMar 21 2019We investigate, using angle-resolved photoemission spectroscopy (ARPES), the electronic structure of graphene sandwiched in between two Cs layers with $2\times 2$ and $\sqrt{3}\times\sqrt{3}$ structures. ARPES reveals that this trilayer has a flat electron ... More

Collective dynamics of Fermi-Bose mixtures with an oscillating scattering lengthMar 21 2019Collective oscillations of superfluid mixtures of ultra cold fermionic and bosonic atoms are investigated while varying the fermion-boson scattering length. We study the dynamics with respect to excited center of mass modes and breathing modes in the ... More

Constraints on order and disorder parameters in quantum spin chainsMar 21 2019We derive general constraints on order and disorder parameters in Ising symmetric spin chains. Our main result is a theorem showing that every gapped, translationally invariant, Ising symmetric spin chain has either a nonzero order parameter or a nonzero ... More

Room temperature and low-field resonant enhancement of spin Seebeck effect in partially compensated magnetsMar 21 2019Resonant enhancement of spin Seebeck effect (SSE) due to phonons was recently discovered in Y3Fe5O12 (YIG). This effect is explained by hybridization between the magnon and phonon dispersions. However, this effect was observed at low temperatures and ... More

Zero-energy vortices in Dirac materialsMar 21 2019In this brief review, we survey the problem of electrostatic confinement of massless Dirac particles, via a number of exactly solvable one- and two-body models. By considering bound states at zero energy, we present a route to obtain truly discrete states ... More

Lithium Diffusion in Li2X(X=O, S and Se): Ab-initio Simulations and Neutron Inelastic Scattering MeasurementsMar 21 2019We have performed ab-initio lattice dynamics and molecular dynamics studies of Li2X (X=O, S and Se) to understand the ionic conduction in these compounds. The inelastic neutron scattering measurements on Li2O have been performed across its superionic ... More

Spin relaxation in fluorinated single and bilayer grapheneMar 21 2019We present a joint experiment-theory study on the role of fluorine adatoms in spin and momentum scattering of charge carriers in dilute fluorinated graphene and bilayer graphene. The experimental spin-flip and momentum scattering rates and their dependence ... More

Liquid-phase exfoliated indium-selenide flakes and their application in hydrogen evolution reactionMar 21 2019Single- and few-layered InSe flakes are produced by the liquid-phase exfoliation of beta-InSe single crystals in 2-propanol, obtaining stable dispersions with a concentration as high as 0.11 g/L. Ultracentrifugation is used to tune the morphology, i.e., ... More

WS2-graphite dual-ion batteryMar 21 2019A novel WS2-graphite dual-ion battery (DIB) is developed by combining together a conventional graphite cathode and high-capacity few-layer WS2 flakes anode. The WS2 flakes are produced by exploiting wet-jet milling (WJM) exfoliation, which allows mass ... More

Engineered MoSe2-based heterostructures for efficient electrochemical hydrogen evolution reactionMar 21 2019Two-dimensional transition metal-dichalcogenides are emerging as efficient and cost-effective electrocatalysts for hydrogen evolution reaction (HER). However, only the edge sites of their trigonal prismatic phase show HER-electrocatalytic properties, ... More

Doped-MoSe2 nanoflakes/3d metal oxide-hydr(oxy)oxides hybrid catalysts for pH-universal electrochemical hydrogen evolution reactionMar 21 2019Clean hydrogen production through efficient and cost-effective electrochemical water splitting is highly promising to meeting future global energy demands. The design of Earth-abundant materials with both high activity for hydrogen evolution reaction ... More

Biotransformation and biological impact of graphene and graphene oxide during simulated oral ingestionMar 21 2019Graphene is an innovative nanomaterial, made of two-dimensional honeycomb-like carbon lattice, with potential in many different applications. Studying the behaviour of graphene-related materials (GRMs) in biological systems is, therefore, crucial to assess ... More

Fractional Brownian motion in a finite interval: correlations effect depletion or accretion zones of particles near boundariesMar 21 2019Fractional Brownian motion is a Gaussian stochastic process with stationary, long-time correlated increments and is frequently used to model anomalous diffusion processes. We study numerically fractional Brownian motion confined to a finite interval with ... More

Dzyaloshinskii-Moriya interaction and the magnetic ground state in magnetoelectric LiCoPO$_4$Mar 21 2019Magnetic structures are investigated by means of neutron diffraction to shine a light on the intricate details that are believed to be key to understanding the magnetoelectric effect in LiCoPO$_4$ . At zero field, a spontaneous spin canting of $\varphi ... More

Tomonaga-Luttinger liquid in a box: electrons confined within MoS$_2$ mirror twin boundariesMar 21 2019Two- or three-dimensional metals are usually well described by weakly interacting, fermionic quasiparticles. This concept breaks down in one dimension due to strong Coulomb interactions. There, low-energy electronic excitations are expected to be bosonic ... More

Electromagnetic design of a superconducting electric machine with bulk HTS materialMar 21 2019The use of high-temperature superconductors in electric machines offers potentially large gains in performance compared to conventional conductors, but also comes with unique challenges. Here, the electromagnetic properties of superconducting electric ... More

Viscosity measurements in pulsed magnetic fields by using a quartz-crystal microbalanceMar 21 2019Viscosity measurements in combination with pulsed magnetic fields are developed by use of a quartz-crystal microbalance (QCM). When the QCM is immersed in liquid, the resonant frequency, $f_0$, and the quality factor, $Q$, of the QCM change depending ... More

Circumventing the no-go theorem: A single Weyl point surrounded by nodal wallsMar 21 2019Despite of a rapidly expanding inventory of possible crystalline Weyl semimetals, all of them are constrained by the Nielsen-Ninomiya no-go theorem, namely, that left- and right-handed Weyl points appear in pairs. With time-reversal (T) symmetry, an even ... More

High thermal conductivity of high-quality monolayer boron nitride and its thermal expansionMar 21 2019Heat management becomes more and more critical, especially in miniaturized modern devices, so the exploration of highly thermally conductive materials with electrical insulation and favorable mechanical properties is of great importance. Here, we report ... More

Stabilization and heteroepitaxial growth of metastable tetragonal FeS thin films by pulsed laser depositionMar 21 2019Pulsed laser deposition, a non-equilibrium thin-film growth technique, was used to stabilize metastable tetragonal iron sulfide (FeS), the bulk state of which is known as a superconductor with a critical temperature of 4 K. Comprehensive experiments revealed ... More

Magnetic and electrical anisotropy with correlation and orbital effects in dimerized honeycomb ruthenate Li$_2$RuO$_3$Mar 21 2019Li2RuO3 undergoes a structural transition at a relatively high temperature of 550 K with a distinct dimerization of Ru-Ru bonds on the otherwise isotropic honeycomb lattice. It exhibits a unique herringbone dimerization pattern with a largest ever reported ... More

Impact of Temperature-Dependent Rattling Phonons on Lattice Thermal Transport in Ag$_{6}$Ge$_{10}$P$_{12}$Mar 21 2019Crystalline compounds exhibiting low-frequency rattling phonons constitute an important class of high-performance thermoelectrics owning to their intrinsically very low lattice thermal conductivity ($\kappa_{l}$). Theoretical approach that is capable ... More

Magnetic Skyrmions in Atomic Thin CrI$_3$ MonolayerMar 21 2019In this letter, we report the visualization of topologically protected spin textures, in the form of magnetic skyrmions, in recently discovered monoatomic-thin two-dimensional CrI$_3$. By combining density functional theory and atomistic spin dynamic ... More

A Reciprocal Formulation of Nonexponential Radiative Transfer. 3: Binary MixturesMar 21 2019We derive the form of reciprocal generalized radiative transfer (RGRT) that includes the Levermore-Pomraning attenuation law for paths leaving a deterministic origin. The resulting model describes linear transport within multi-dimensional stochastic binary ... More

Hidden Asymptotic Symmetry in Long Elastic Beams on Softening FoundationsMar 20 2019Transverse wrinkles are known to appear in thin rectangular elastic sheets when stretched in the long direction. Numerically computed bifurcation diagrams for extremely thin, highly stretched films indicate entire orbits of wrinkling solutions, cf. Healey, ... More

Multi-band non-equilibrium GW+EDMFT formalism for correlated insulatorsMar 20 2019We study the dynamics of charge-transfer insulators after a photo-excitation using the three-band Emery model which is relevant for the description of cuprate superconductors. We provide a detailed derivation of the nonequilibrium extension of the multi-band ... More

Electric-field induced helium-helium resonancesMar 20 2019The tunability of the helium-helium interaction through an external electric field is investigated. For a static external field, electric-field induced resonances and associated electric-field induced bound states are calculated for the $^4$He-$^4$He, ... More

Theory of correlated insulating behaviour and spin-triplet superconductivity in twisted double bilayer grapheneMar 20 2019Two monolayers of graphene twisted by a small `magic' angle exhibit nearly flat bands leading to correlated electronic states and superconductivity, whose precise nature including possible broken symmetries, remain under debate. Here we theoretically ... More

Vortex lattice in a uniform Bose-Einstein condensate in a box trapMar 20 2019We study numerically the vortex-lattice formation in a rapidly rotating uniform quasi-two-dimensional Bose-Einstein condensate (BEC) in a box trap. We consider two types of boxes: square and circle. In a square-shaped 2D box trap, when the number of generated ... More

Two-Fluid Hydrodynamics and Viscosity Suppression in Fluctuating SuperconductorsMar 20 2019We consider a fluctuating superconductor in the vicinity of the transition temperature, $T_c$. The fluctuation shear viscosity is calculated. In two dimensions, the leading correction to viscosity is negative and scales as $\delta \eta(T) \propto \ln(T-T_c)$. ... More

$π$-fluxes, semi-metals and flat bands in artificial materialsMar 20 2019The possibility of engineering experimentally viable systems that realize gauge fluxes within plaquettes of hopping have been subject of search for decades due to vast amounts of theoretical study. This is of particular interest for topological band insulators, ... More

Modelling and optimization of the excitonic diffraction gratingMar 20 2019Mar 21 2019Periodical spatial modulation of the excitonic resonance in a quantum well could lead to the formation of a new highly directional and resonant coherent optical response -- resonant diffraction. Such excitonic diffraction gratings were demonstrated in ... More