Motivated by the recent experimental progress in exploring the use of a nitrogen-vacancy (NV) center in diamond as a quantum computing platform, we propose schemes for fast and high-fidelity entangling gates on this platform. Using both analytical and numerical calculations, we demonstrate that synchronization effects between resonant and off-resonant transitions may be exploited such that spin-flip

Characteristics of magneto-electro-elastic effects in a diamond with negatively charged nitrogen vacancy centers are calculated analytically. It is predicted that strains or the external electric field can cause the onset of projections of the magnetic moment of those vacancies perpendicular to the applied magnetic field. It is shown how spins of those vacancies produce the anisotropy of the electric

Both Kitaev and Dzyaloshinskii-Moriya interactions (DMI) are known to promote intrinsic contributions to the magnon Hall effects such as the thermal Hall and the spin Nernst effects in collinear magnets. Previously, it was reported that a sign change in those transversal transport coefficients only appears in the presence of Kitaev interaction, but not for DMI, which qualitatively distinguishes both

As is well known, magnetic impurities adsorbed on superconductors, e.g., of the s-wave type, can introduce a bound gap-state (Yu-Shiba-Rusinov resonance). We here investigate within a minimal model how the impurity moment arranges with respect to a weak homogeneous internal magnetic field employing a fully self-consistent mean-field treatment. Our investigation reveals a critical window of impurity-to-substrate

In the framework of the Keldysh formalism and the tight-binding model, we investigate spin-orbit phenomena such as the anomalous and spin Hall effects, tunneling anisotropic magnetoresistance, and Rashba-induced spin-orbit torque in single-barrier tunnel junctions. We focus on two configurations: one with a ferromagnetic metal [normal metal (NM)/insulator (I)/ferromagnetic metal (FM)] and the other

We investigated surface acoustic wave (SAW) propagation and lattice vibrations in two-dimensional (2D) titanium carbide (Ti3C2Tx) MXene films as a function of surface termination and layer stacking, using atomistic simulations. We found that SAW propagation velocity is highly sensitive to both single-layer properties and interlayer bonding. Surface terminations significantly modulate wave behavior

The nonstoichiometric Fe2P-type FeMn(1−x)Vx(P0.5Si0.5)1−x alloys (x=0,0.01, 0.02, and 0.03) have been investigated as potential candidates for magnetic refrigeration near room temperature. The magnetic ordering temperature decreases with increasing FeV concentration x, which can be ascribed to decreased ferromagnetic coupling strength between the magnetic atoms. The strong magnetoelastic coupling in

The role of layer disorder is important in establishing the topological phases of MoTe2. A rich tapestry of atomic ordering influences the structural phase transitions (SPTs), but there is little understanding of the mechanistic details of the phase transition. An atomistic level study was conducted to investigate the local structure of the 1T′ and Td phases of MoTe2 by using the pair distribution

Bright sources of quantum microwave light are an important building block for various quantum technological applications. Josephson junctions coupled to microwave cavities are a particularly versatile and simple source for microwaves with quantum characteristics, such as different types of squeezing. Due to the inherent nonlinearity of the system, a pure dc-voltage bias can lead to the emission of

We provide solid evidence for the long-standing presumption that model Hamiltonians with short-range interactions faithfully reproduce the physics of the long-range Coulomb interaction in real materials. For this aim, we address a generic Hubbard model that captures the quantum phase transitions between metal, Mott insulator, and charge-density-wave (CDW) insulator, in the absence of Fermi-surface

We use an exact Moreau-Yosida regularized formulation to obtain the exchange-correlation potential for periodic systems. We reveal a profound connection between rigorous mathematical principles and efficient numerical implementation, which marks a successful application of a Moreau-Yosida-based inversion for physical systems. We develop a mathematically rigorous inversion algorithm that is demonstrated

In recent years, there has been a surge of interest in exploring higher-order topology and their semimetallic counterparts, particularly in the context of Dirac, Weyl, and nodal line semimetals, termed higher-order Dirac semimetals (HODSM), higher-order Weyl semimetals, and higher-order nodal line semimetals (HONLSM). The HODSM phase exhibits hinge Fermi arcs (FAs) with a quantized higher-order topological

The common model to describe exciton-plasmon interaction phenomenologically is the coupled oscillator model. Originally developed for atomic systems rather than solid-state matter, this model treats both excitons and plasmons as single harmonic oscillators coupled via a constant which can be fitted to experiments. In this paper, we present a modified coupled oscillator model specifically designed for

Swift electrons passing near or through metallic structures have proven to be an excellent tool for studying plasmons and other types of confined optical modes involving collective charge oscillations in the material structures hybridized with electromagnetic fields. In this work, we provide a general analytical framework for the simulation of electron energy-loss spectroscopy (EELS) in infinite systems

Magnetic hopfions are three-dimensional topological solitons with nonzero Hopf index H in the vector field of material's local magnetization. Here elliptical stability of hopfions with H=1 in a classical helimagnet is studied on the basis of a variational model. It is shown that, depending on their internal structure (vortex and antivortex tubes ordering), the hopfions can be either stable in a bulk

Two-particle interferometry is an important tool for extracting the exchange statistics of quantum particles. We theoretically investigate the prospects of such interferometry to probe the statistics of pointlike anyonic excitations injected in a Hong-Ou-Mandel (HOM) setup based on a quantum point contact device in the fractional quantum Hall regime. We compute the standard HOM ratio, i.e., the ratio

We investigate the easy-axis Heisenberg model on the triangular lattice by numerically studying excitations and the dynamical spin structure factor Sμμ(q,ω). Results are analyzed within the supersolid scenario, characterized by the translation-symmetry-breaking parameter mz and the supersolid offdiagonal order parameter m⊥. We find very robust mz>0 in the whole easy-axis anisotropy regime α=J⊥/Jz>0

We present a numerical approach to calculate inelastic light scattering spectra from gold nanocrystals, based on the finite element method. This approach is validated by comparison with previous analytic calculations for spherically symmetric scatterers. Superellipsoid nanocrystals are considered in order to smoothly vary the shape from octahedra to cubes via spheres, while preserving cubic symmetry

Fading ergodicity provides a theoretical framework for understanding deviations from the eigenstate thermalization hypothesis (ETH) near ergodicity-breaking transitions. In this work we demonstrate that the position of the ergodicity-breaking critical point in the quantum sun model coincides with the peak of the maximally divergent fidelity susceptibility. We further extend our analysis to the energy-resolved

In two dimensional magnets, the interplay of thermal fluctuations and spin anisotropy control the existence of long-range magnetic order. In the van der Waals antiferromagnets FePX3, orbital degeneracy in the t2g levels of the Fe2+ ions in octahedral coordination yields strong uniaxial anisotropy, which stabilizes magnetic order up to T≈100 K. Recent inelastic neutron scattering measurements around

Recent experiments on planar superconductor-topological insulator-superconductor (S-TI-S) junctions, e.g., in the Corbino geometry, have reported low-temperature nonzero Josephson currents in states with integer fluxoid (flux) induced in the junction by a perpendicular magnetic field. This effect was discussed in connection with Majorana zero modes localized in Josephson vortices of such junctions

Interaction-induced charge orders with electronic origin occur as states of spontaneously broken symmetry in several materials platforms. An electronic mechanism for charge order requires an attractive component in the effective charge vertex. We put forward such a mechanism for the formation of unconventional charge density waves in a metal. These states result from the condensation of particle-hole

Starting from a double quantum dot realization of a minimal Kitaev chain, we demonstrate that non-Hermiticity stabilizes the so-called poor man's Majorana zero modes in a region of parameter space that is much broader than in the Hermitian regime. In particular, we consider the simplest non-Hermitian mechanism which naturally appears due to coupling to normal reservoirs and is commonly present in all

In AM4X8 lacunar spinel systems, the formation of structural clusters in Td symmetry has led to the systems and its properties being commonly described by a M4 molecular orbital picture and its associated spin, charge, and orbital degrees of freedom. However, the nature of the molecular orbital states in the cluster is yet to be elucidated by means of photoemission spectroscopy. Here, we show that

Weakly and strongly interacting quantum many-body systems, namely semiconductors and Mott insulators, are combined into a layered heterostructure. Via the hierarchy of correlations, we derive and match the propagating quasiparticle solutions in the different regions and calculate the transmission coefficients through these layered structures. As a proof of principle, we find the well-known transmission

Effective control of spin-wave (SW) dynamics is among the current topical goals of research in magnonics. Electric field control of SW dynamics in insulating magnetic materials by creating the Aharonov-Casher (AC) topological phase without energy dissipation due to joule heating is a highly preferred way. The AC phase is purely a quantum phenomenon and has no classical interpretation. It manifests

The question of thermalization of a closed quantum system is of central interest in nonequilibrium quantum many-body physics. Here we present one such study analyzing the dynamics of a closed coupled Majorana SYK system. We have a large-q SYK model prepared initially at equilibrium quenched by introducing a random hopping term, thus leading to nonequilibrium dynamics. We find that the final stationary

Artificial magnetic domains are induced into a soft-magnetic in-plane Co60Fe20B19Si1 (CoFeBSi) alloy by interlayer coupling to a perpendicular-to-plane FePt underlayer. We present images documenting the thickness dependence of the size of magnetic domains inside the CoFeBSi ferromagnetic layer. The magnetic domain walls in FePt induce a continuous progression of domain walls into the CoFeBSi at the

We have investigated the quasi-one-dimensional Ni-chain compound PbMn2Ni6Te2O18 using theoretical DFT calculations, inelastic neutron scattering, and optical spectroscopy in order to understand the nature of magnetic exchange interactions. Our inelastic neutron scattering study at 5 K on a powder sample reveals two bands of magnetic excitations, the first near 8 meV and the second near 18 meV originating

We investigate quantum phase transitions in a topological Josephson junction with an embedded ferromagnetic layer, revealing a rich landscape of critical phenomena. The low-energy excitations comprise Majorana fermions propagating along the junction, coupled to the magnons in the ferromagnet. Based on mean-field and renormalization group arguments, we predict Berezinskii-Kosterlitz-Thouless (BKT) transitions

Altermagnetism became very popular because of unique features, namely coupling between magnetic properties and momentum of itinerant electrons. The particular model of the altermagnetic system of our interest has already been studied in recent publications in a different context: . Here, we study the scattering process of an itinerant electron from the altermagnetic material on the electron localized

Electron energy-loss spectroscopy in transmission is applied to investigate the dependence of the exciton energies on the momentum, q, in the bulk of 2H−WSe2. The exciton dispersion E(q) for momentum vectors parallel to the ΓK direction and the ΓM direction at room temperature as well as at 20 K close to the K point is investigated. In addition, the exciton spectra at room temperature are measured

We report temperature-dependent reflectivity spectra of the layered van der Waals magnet CrSBr in the far-infrared region. Polarization-dependent measurements resolve the vibrational modes along the E∥a and b axes and reveal clear structural anisotropy. While the a-axis phonons notably harden on cooling, the b-axis phonon frequencies are almost temperature independent. A phonon splitting due to the

The bulk photovoltaic effect is a photocurrent generation from alternating electric field, which is a promising candidate for future efficient solar cell technology. It is the second-order optical current, which is the injection current or the shift current. We focus on the direct current generation. By employing a simple two-band model of the d-wave altermagnet coupled with the Rashba interaction

We study an interacting spinless quadratic band touching model that realizes a topological Mott insulating state. We quench the interaction from a value corresponding to the nematic insulator to that of the quantum anomalous Hall (QAH) ordered phase. We perform time-dependent Hartree-Fock simulations and show that after the quench the system realizes an excited Dirac semimetal state, which is, however

Magnetic adatoms on superconductors induce Yu-Shiba-Rusinov (YSR) states, which are key to the design of low-dimensional correlated systems and topological superconductivity. Competing magnetic interactions and superconducting pairing lead to a rich phase diagram. Using a scanning tunneling microscope (STM), we position Fe atoms on 2H−NbSe2 to build a dimer with an odd-parity ground state, i.e., a

Solving for the time evolution of a many particle system whose dynamics is governed by Lindblad equation is hard. We extend the use of the transfer matrix approach to a class of Lindblad equations that admit a closed hierarchy of two point correlators. An example that we treat is the XX spin chain, i.e., free fermions, subject to the local onsite dephasing, but can be extended to other Hermitian dissipators

Skyrmions are nanosized magnetic whirls attractive for spintronic applications due to their innate stability. They can emulate the characteristic behavior of various spintronic and electronic devices such as spin-torque nano-oscillators, artificial neurons and synapses, logic devices, diodes, and ratchets. Here, we show that skyrmions can emulate the physics of an RC circuit—the fundamental electric

The scattering of electrons with polar optical phonons (POP) is an important mechanism that limits electronic transport and determines electron mobility in polar materials. This is typically a stronger mechanism compared to nonpolar acoustic and optical phonon scattering and of similar strength to the Coulomb ionized impurity scattering. At high densities, on the other hand, the cloud of charge carriers

For many materials, Raman spectra are intricately structured and provide valuable information about compositional stoichiometry and crystal quality. Here we use density-functional theory calculations, mass approximation, and the Raman intensity weighted Γ-point density of state approach to analyze Raman scattering and vibrational modes in zincblende, wurtzite, and hexagonal BX (X = N, P, and As) structures

The magnetic insulator Nd3BWO9 has been previously proposed to realize the highly frustrated breathing kagome lattice model. We report a combination of single-crystal neutron scattering studies and numerical simulations that debunk this interpretation. We show that it is the interplane couplings that determine the physics. To explain the exotic magnetism, we derive a simple one-dimensional Ising model

Curvilinear geometries in magnetic nanostructures provide a unique platform for exploring the interplay among symmetry, topology, and curvature in magnetization dynamics. In this paper, we analytically study the static and dynamic properties of magnetic domain walls in biaxial magnetic nanotubes with intrinsic Dzyaloshinskii-Moriya interaction of different symmetries. We show that geometry-driven local

The topological characteristics of Bi and its alloys with Sb have fueled intense debate since the prediction of three-dimensional topological insulators. However, a definitive resolution has not been reached to date. Here, we provide theoretical evidence that surface relaxation conceals the underlying bulk topology of pure Bi. Using density-functional-theory calculations for thin Bi(111) films (up

The optical properties of Janus-type hybrid silicon-gold nanocylinders are theoretically studied. We show that the inhomogeneity of the internal material in these particles causes a strong bianisotropic response. Their lack of inversion symmetry formally determines the bianisotropic response of hybrid nanocylinders. We demonstrate a method for obtaining in advance information on nonzero components

We study in detail the postselection problem in a specific model: bosons hopping on a lattice subjected to continuous local measurements of quadrature observables. We solve the model analytically and show that the postselection overhead can be reduced by postprocessing the entire measurement record into one or two numbers for each trajectory and then binning trajectories based only on these numbers

Antiskyrmions, as topological quasiparticles, hold significant promise for spintronics and nanoscale data storage applications. Using molecular dynamics simulations based on effective Hamiltonians, we investigated the thermal stability of antiskyrmion nanodomains in rhombohedral barium titanate. At 1 K, antiskyrmions with a topological charge of −2 were found to be the most stable nanodomain state

Recent observations of the fractional anomalous quantum Hall effect in moiré materials have reignited the interest in fractional Chern insulators (FCIs). The chiral limit in which analytic Landau-level-like single-particle states form an “ideal” Chern band and local interactions lead to Laughlin-like FCIs at 1/3 filling has been very useful for understanding these systems by relating them to the lowest

We report tunneling spectroscopy and transport measurements in superconducting Al and ferromagnetic insulator EuS bilayers. The samples display remanent spin splitting, roughly half the superconducting gap, and supercurrent transport above the average paramagnetic limit. We interpret this behavior as arising from the interplay between two characteristic length scales: the superconducting coherence

Chiral superconductors are topological as characterized by a finite Chern number and chiral edge modes. Direct fingerprints of chiral superconductivity are thus often taken to be spontaneous edge currents with associated magnetic signatures. However, a number of recent theoretical studies have shown that the total edge current along semi-infinite edges is greatly reduced or even vanishes in many scenarios

We present an computational analysis of the topological Hall effect arising from stable magnetic skyrmions in the Pd/Fe/Ir(111) film using noncollinear spin density functional calculations within the Korringa-Kohn-Rostoker Green function method. The semiclassical Boltzmann transport equation is employed for the resistivity and the Hall angle of the system. We explore the influence of the skyrmion size

Floquet time crystals are characterized by the subharmonic behavior of temporal correlation functions. Studying the paradigmatic time crystal based on the disordered Floquet quantum Ising model, we show that its temporal spin correlations are directly related to spectral characteristics and that this relation provides analytical expressions for the correlation function of finite chains, which compare

We investigate the spin Hall conductivity (SHC) of a composition series of a Ta-Re bcc solid solution. At approximately 60 at.% Ta the Ta-Re alloy features a SHC similar to bcc-W, while both endpoints of the compositional series have rather moderate SHC. The intermediate stoichiometries exhibit a substantial enhancement due to Fermi-level tuning through the same band structure feature which gives bcc-W

Polar metals are an intriguing class of materials that feature a polar crystal structure while also exhibiting metallic conductivity. The unique properties of polar metals challenge expectations, making way for the exploration of exotic phenomena such as unconventional magnetism, hyperferroelectric multiferroicity, and the development of multifunctional devices that can leverage both the material's

Topological band structures interfering with moiré superstructures give rise to a plethora of emergent phenomena, which are pivotal for correlated insulating and superconducting states of twisttronics materials. While quasiperiodicity was up to now a notion mostly reserved for solid-state materials and cold atoms, we here demonstrate the capacity of conventional superconducting circuits to emulate

The formation of two-band nodal points in gapless topological phases, referred to as conventional Weyl nodes, relies solely on translational symmetry. However, when coupled with other spatial and spatiotemporal symmetries, unconventional Weyl nodes with pronounced chirality, high degeneracy, and complementary quaternion charges can manifest. In this paper, we identify ReO3 as an ideal unconventional

Zero-field magnetic noise, characterized by the magnetic autocorrelation function Ss(t), has been observed, perhaps surprisingly, to depend on sample shape s. The reasons for this are identified and general expressions are derived that relate the autocorrelation functions for systems of different shape to an underlying “intrinsic” form. Assuming the fluctuation-dissipation theorem, it is shown that

The effect of high-energy electron irradiation on the temperature dependences of the resistivity ρ(), fluctuation conductivity (FLC), and pseudogap (PG) Δ*() of YBa2Cu3O7−δ (YBCO) single crystals containing virtually no twins was studied. A linear increase in the resistivity and a linear decrease in the superconducting (SC) transition temperature Tc with increasing irradiation doses φ were observed

Altermagnets are a newly identified type of collinear antiferromagnetism with vanishing net magnetic moment, characterized by lifted Kramers' degeneracy in parts of the Brillouin zone. Their time-reversal symmetry-broken band structure has been observed experimentally and is theoretically well understood. On the contrary, altermagnetic fluctuations and the formation of the corresponding instabilities

Ferro-/ferri- and antiferromagnetically ordered phases are typically exclusive in nature, thus, their coexistence in atomic-scale proximity is expected only in heterostructures. Breaking this paradigm and broadening the range of unconventional magnetic states, we report here on the observation of a new, atomic-scale hybrid spin state. This ordering is stabilized in three-dimensional crystals of the

We investigate spin dynamics in α−Fe2O3/Ni80Fe20 (Py) heterostructures, uncovering a robust mechanism for designing the ferromagnetic resonance (FMR) frequency through control of crystal orientation, temperature, and applied magnetic field. Employing cryogenic ferromagnetic resonance spectroscopy, we demonstrate that the relative orientation of the Néel vector of α−Fe2O3 and the magnetization of the