arXiv subjects

Jagoda Slawinska

Publications and source records attributed to Jagoda Slawinska.

13 recordsLinked to original sources

arXiv2026

PAOFLOW: an automated suite for ab initio electronic, transport, and topological properties of materials

High-throughput first-principles property calculations are often constrained by costly post-processing and dense Brillouin-zone sampling, impeding the creation of large, internally consistent materials-property datasets and limiting AI-driven discovery workflows. Pseudo-atomic-orbital (PAO) Hamiltonians provide an exact tight-binding representation of first-principles electronic structure that enables the calculation of a wide range of electronic, optical, topological, and transport properties at negligible cost, thereby supporting scalable generation of training-quality data and AI-ready data infrastructures. In this work, we present PAOFLOW 3.0 -- an open-source Python suite that automates the construction and analysis of PAO Hamiltonians from plane-wave density functional theory calculations performed with either Quantum ESPRESSO or VASP. The resulting Hamiltonians enable efficient electronic structure interpolation, Fermi surface analysis, optical and dielectric response, transport coefficients, Berry phase and topological quantities, quantum transport, and other materials properties. Compared with previous releases, PAOFLOW 3.0 substantially extends the scope of the package through the introduction of internal projections enabling support for VASP calculations, self-consistent Hubbard U and V corrections obtained using ACBN0 and eACBN0 methods, generation of environment-dependent Slater-Koster tight-binding models, Landauer--BÃŒttiker quantum transport, and calculation of quantum oscillations using the integrated PySKEAF module. The theoretical foundations and the software architecture are presented together with representative calculations illustrating the current capabilities of the package.

cond-mat.mtrl-sci↗

arXiv2026

Universal unconventional responses controlled by ferroaxial order

Ferroaxial materials are an emerging class of ferroic materials that, in contrast to ferromagnets and ferroelectrics, are fully robust against stray fields, making them ideally suited for data storage and other nonvolatile applications. However, detection of the ferroaxial state remains challenging, as ferroaxiality does not manifest directly through a measurable macroscopic electric polarization or magnetization, and probes are mostly limited to optical methods. Here, we theoretically establish that ferroaxial order universally generates unconventional components of responses to external stimuli, such as the spin Hall effect, magneto-Seebeck effect, or Faraday effect, across a broad range of linear and nonlinear transport, optical and equilibrium phenomena. These unconventional responses are always directly coupled to ferroaxial order and can distinguish ferroaxial domains, providing probes of ferroaxial order. This general connection also reveals a largely unexplored class of ferroaxial metals, in which unconventional transport provides a natural probe of ferroaxial order, as demonstrated by our first-principles calculations for representative materials. Our results reveal a fundamentally different way for ferroic order to manifest -- ferroaxiality primarily shows unconventional material responses rather than the directly measurable order parameters, broadening the possibilities of nonvolatile ferroic control and flexible device design.

cond-mat.mtrl-sci↗

arXiv2025

Persistent spin texture preserved by local symmetry in graphene/WTe$_2$ heterostructure

Crystal symmetries in solids give rise to spin-momentum locking, which determines how an electron's spin orientation depends on its momentum. This relationship, often referred to as spin texture, influences both charge-to-spin conversion and spin relaxation, making it one of the essential characteristics for spin-orbit-driven phenomena. Materials with strong spin-orbit coupling and broken inversion symmetry can host persistent spin textures (PSTs) - unidirectional spin configurations in momentum space, supporting efficient charge-to-spin conversion and extended spin lifetimes. Monolayer WTe$_2$, a topological material crystallizing in a rectangular lattice, is a notable example; its symmetry enforces a canted PST enabling quantum spin Hall effect with the nontrivial spin orientation. Here, we use first-principles calculations to explore how these properties are modified when WTe$_2$ is interfaced with graphene. We find that the PST is preserved by the local symmetry present in different regions of the heterostructure, while the system develops extended electron and hole pockets, resulting in semimetallic behavior. Although the band gap closes and eliminates the quantum spin Hall phase, spin Hall effects remain robust in both conventional and unconventional geometries. The computed spin Hall conductivities are comparable to those of other two-dimensional materials, and the survival of the PST suggests the possibility of long-range spin transport even in the absence of topological edge states. In addition, the graphene layer serves as an oxidation barrier, helping protect the intrinsic properties of WTe$_2$ and supporting the potential of this heterostructure for spintronic applications.

cond-mat.mtrl-sci↗

arXiv2025

Persistent spin textures, altermagnetism and charge-to-spin conversion in metallic chiral crystals TM$_{3}$X$_{6}$

Chiral crystals, due to the lack of inversion and mirror symmetries, exhibit unique spin responses to external fields, enabling physical effects rarely observed in high-symmetry systems. Here, we show that materials from the chiral dichalcogenide family TM$_3$X$_6$ (T = 3d, M = 4d/5d, X = S) exhibit persistent spin texture (PST) - unidirectional spin polarization of states across large regions of the reciprocal space - in their nonmagnetic metallic phase. Using the example of NiTa$_{3}$S$_{6}$ and NiNb$_{3}$S$_{6}$, we show that PSTs cover the full Fermi surface, a rare and desirable feature that enables efficient charge-to-spin conversion and suggests long spin lifetimes and coherent spin transport above magnetic ordering temperatures. At low temperatures, the materials that order antiferromagnetically become chiral altermagnets, where spin textures originating from spin-orbit coupling and altermagnetism combine in a way that sensitively depends on the orientation of the Neel vector. Using symmetry analysis and first-principles calculations, we classify magnetic ground states across the family, identify cases with weak ferromagnetism, and track the evolution of spin textures and charge-to-spin conversion across magnetic phases and different Neel vector orientations, revealing spin transport signatures that allow one to distinguish Neel vector directions. These findings establish TM$_3$X$_6$ as a tunable platform for efficient charge-to-spin conversion and spin transport, combining structural chirality, persistent spin textures, and altermagnetism.

cond-mat.mtrl-sci↗

arXiv2024

Universal symmetry-protected persistent spin textures in nonmagnetic solids

The significance of Mendeleev's periodic table extends beyond the classification of elements; it lies in its remarkable predictive power for discovering new elements and properties, revealing the underlying symmetrical patterns of nature that were only fully understood with the advent of quantum mechanics. Fundamental material properties, such as electron transport and magnetism, are also governed by crystal symmetry. In particular, spin transport depends on the spin polarization of electronic states, and recently discovered materials where the electron spin polarization is independent of momentum - a property known as a persistent spin texture (PST) - promise extended spin lifetime and efficient spin accumulation. In this paper, we establish the general conditions for the existence of symmetry-protected PST in bulk crystals. By systematically analyzing all 230 crystallographic space groups, similar to elements in the periodic table, we demonstrate that PST is universally present in all nonmagnetic solids lacking inversion symmetry. Using group theory, we identify the regions within the Brillouin zone that host PST and determine the corresponding directions of spin polarization. Our findings, supported by first-principles calculations of representative materials, open the route for discovering robust spintronic materials based on PST.

cond-mat.mtrl-sci↗

arXiv2024

Nonlinear magnetotransport in MoTe${}_2$

The shape of the Fermi surface influences many physical phenomena in materials and a growing interest in how the spin-dependent properties are related to the fermiology of crystals has surged. Recently, a novel current-dependent nonlinear magnetoresistance effect, known as bilinear magnetoelectric resistance (BMR), has been shown to be not only sensitive to the spin-texture in spin-polarized non-magnetic materials, but also dependent on the convexity of the Fermi surface in topological semimetals. In this paper, we show that the temperature dependence of the BMR signal strongly depends on the crystal axis of the semimetallic MoTe${}_2$. For the a-axis, the amplitude of the signal remains fairly constant, while for the b-axis it reverses sign at about 100 K. We calculate the BMR efficiencies at 10 K to be $χ^{J}_{A} = (100\pm3)$ nm${}^2$T${}^{-1}$A${}^{-1}$ and $χ^{J}_{B} = (-364\pm13)$ nm${}^2$T${}^{-1}$A${}^{-1}$ for the a- and b-axis, respectively, and we find that they are comparable to the efficiencies measured for WTe${}_2$. We use density functional theory calculations to compute the Fermi surfaces of both phases at different energy levels and we observe a change in convexity of the outer-most electron pocket as a function of the Fermi energy. Our results suggest that the BMR signal is mostly dominated by the change in the Fermi surface convexity.

cond-mat.mes-hall↗

arXiv2023

Crystallographic-dependent bilinear magnetoelectric resistance in a thin WTe$_2$ layer

The recently reported Bilinear Magnetoeletric Resistance (BMR) in novel materials with rich spin textures, such as bismuth selenide (Bi$_2$Se$_3$) and tungsten ditelluride (WTe$_2$), opens new possibilities for probing the spin textures via magneto-transport measurements. By its nature, the BMR effect is directly linked to the crystal symmetry of the materials and its spin texture. Therefore, understanding the crystallographic dependency of the effect is crucial. Here we report the observation of crystallographic-dependent BMR in thin WTe$_2$ layers and explore how it is linked to its spin textures. The linear response measured in first harmonic signals and the BMR measured in second harmonic signals are both studied under a wide range of magnitudes and directions of magnetic field, applied current and at different temperatures. We discover a three-fold symmetry contribution of the BMR when current is applied along the a-axis of the WTe$_2$ thin layer at 10 K, which is absent for when current is applied along the b-axis.

cond-mat.mes-hall↗

arXiv2019

Persistent spin helix in Rashba-Dresselhaus ferroelectric CsBiNb2O7

Ferroelectric Rashba semiconductors (FERSC) are a novel class of multifunctional materials showing a giant Rashba spin splitting which can be reversed by switching the electric polarization. Although they are excellent candidates as channels in spin field effect transistors, the experimental research has been limited so far to semiconducting GeTe, in which ferroelectric switching is often prevented by heavy doping and/or large leakage currents. Here, we report that CsBiNb2O7, a layered perovskite of Dion-Jacobson type, is a robust ferroelectric with sufficiently strong spin-orbit coupling and spin texture reversible by electric field. Moreover, we reveal that its topmost valence band's spin texture is quasi-independent from the momentum, as a result of the low symmetry of its ferroelectric phase. The peculiar spin polarization pattern in the momentum space may yield the so-called "persistent spin helix", a specific spin-wave mode which protects the spin from decoherence in diffusive transport regime, potentially ensuring a very long spin lifetime in this material.

cond-mat.mtrl-sci↗

arXiv2019

Spin-orbit proximity effect in graphene on metallic substrates: decoration vs intercalation with metal adatoms

The so-called spin-orbit proximity effect experimentally realized in graphene (G) on several different heavy metal surfaces opens a new perspective to engineer the spin-orbit coupling (SOC) for new generation spintronics devices. Here, via large-scale density functional theory (DFT) calculations performed for two distinct graphene/metal models, G/Pt(111) and G/Au/Ni(111), we show that the spin-orbit splitting of the Dirac cones (DCs) in these stuctures might be enhanced by either adsorption of adatoms on top of graphene (decoration) or between the graphene and the metal (intercalation). While the decoration by inducing strong graphene-adatom interaction suppresses the linearity of the G's $π$ bands, the intercalated structures reveal a weaker adatom-mediated graphene/substrate hybridization which preserves well-defined although broadened DCs. Remarkably, the intercalated G/Pt(111) structure exhibits splittings considerably larger than the defect-free case.

cond-mat.mtrl-sci↗

arXiv2019

Fe/GeTe(111) heterostructures as an avenue towards 'ferroelectric Rashba semiconductors'-based spintronics

By performing density functional theory (DFT) and Green's functions calculations, complemented by X-ray Photoemission Spectroscopy, we investigate the electronic structure of Fe/GeTe(111), a prototypical ferromagnetic/Rashba-ferroelectric interface. We reveal that such system exhibits several intriguing properties resulting from the complex interplay of exchange interaction, electric polarization and spin-orbit coupling. Despite a rather strong interfacial hybridization between Fe and GeTe bands, resulting in a complete suppression of the surface states of the latter, the bulk Rashba bands are hardly altered by the ferromagnetic overlayer. This could have a deep impact on spin dependent phenomena observed at this interface, such as spin-to-charge interconversion, which are likely to involve bulk rather than surface Rashba states.

cond-mat.mtrl-sci↗

arXiv2019

Absorption and emission modulation in MoS2-GaN (0001) heterostructure by interface phonon-exciton coupling

Semiconductor heterostructures based on layered two-dimensional transition metal dichalcogenides (TMD) interfaced to gallium nitride (GaN) are excellent material systems to realize broadband light emitters and absorbers. The surface properties of the polar semiconductor, such as GaN are dominated by interface phonons, thus the optical properties of the vertical heterostructure depend strongly on the interface exciton-phonon coupling. The origin and activation of different Raman modes in the heterostructure due to coupling between interfacial phonons and optically generated carriers in a monolayer MoS2-GaN (0001) heterostructure was observed. This coupling strongly influences the non-equilibrium absorption properties of MoS2 and the emission properties of both semiconductors. Density functional theory (DFT) calculations were performed to study the band alignment of the interface, which revealed a type-I heterostructure. The optical excitation with interband transition in MoS2 at K-point strongly modulates the C excitonic band in MoS2. The overlap of absorption and emission bands of GaN with the absorption bands of MoS2 induces the energy and charge transfer across the interface with an optical excitation at Γ-point. A strong modulation of the excitonic absorption states is observed in MoS2 on GaN substrate with transient optical pump-probe spectroscopy. The interaction of carriers with phonons and defect states leads to the enhanced and blue shifted emission in MoS2 on GaN substrate. Our results demonstrate the relevance of interface coupling between phonons and carriers for the development of optical and electronic applications.

cond-mat.mtrl-sci↗

arXiv2019

Giant spin Hall Effect in two-dimensional monochalcogenides

One of the most exciting properties of two dimensional materials is their sensitivity to external tuning of the electronic properties, for example via electric field or strain. Recently discovered analogues of phosphorene, group-IV monochalcogenides (MX with M = Ge, Sn and X = S, Se, Te), display several interesting phenomena intimately related to the in-plane strain, such as giant piezoelectricity and multiferroicity, which combine ferroelastic and ferroelectric properties. Here, using calculations from first principles, we reveal for the first time giant intrinsic spin Hall conductivities (SHC) in these materials. In particular, we show that the SHC resonances can be easily tuned by combination of strain and doping and, in some cases, strain can be used to induce semiconductor to metal transitions that make a giant spin Hall effect possible even in absence of doping. Our results indicate a new route for the design of highly tunable spintronics devices based on two-dimensional materials.

cond-mat.mtrl-sci↗

arXiv2018

Complex spin texture of Dirac cones induced via spin-orbit proximity effect in graphene on metals

We use large-scale DFT calculations to investigate with unprecedented detail the so-called spin-orbit (SO) proximity effect in graphene adsorbed on the Pt(111) and Ni(111)/Au semi-infinite surfaces, previously studied via spin and angle resolved photoemission (SP-ARPES) experiments. The key finding is that, due to the hybridization with the metal's bands, the Dirac cones manifest an unexpectedly rich spin texture including out-of-plane and even radial in-plane spin components at (anti)crossings where local gap openings and deviations from linearity take place. Both the continuum character of the metallic bands and the back folding associated to the moiré patterns enhance the spin texture and induce sizable splittings which, nevertheless, only become giant (~100 meV) at anticrossing regions; that is, where electronic transport is suppressed. At the quasilinear regions the splitted bands typically disperse with different broadenings and tend to cross with their magnetization continuously changing in order to match that at the edges of the upper and lower gaps. As a result, both the splittings and spin direction become strongly k dependent. The SO manifests in an analogous way for the spin-polarized G/Au/Ni(111) system, although here the magnetic exchange interactions dominate inducing small splittings (~10 meV) in the $π$ bands while the SO mainly introduces a small Rashba splitting in the Dirac cones as their magnetization acquires a helical component. While revealing such complex spin texture seems challenging from the experimental side, our results provide an important reference for future SP-ARPES measurements of similar graphene based systems extensively investigated for applications in spintronics.

cond-mat.mtrl-sci↗