A5056517324- Topological Materials and Phenomena
- Graphene research and applications
- Advanced Condensed Matter Physics
- 2D Materials and Applications
- Quantum and electron transport phenomena
- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- Surface and Thin Film Phenomena
- Advancements in Battery Materials
- Electronic and Structural Properties of Oxides
- Theoretical and Computational Physics
- Advanced Thermoelectric Materials and Devices
- Iron-based superconductors research
- Magnetic and transport properties of perovskites and related materials
- Aluminum Alloys Composites Properties
- Quantum many-body systems
- Phase-change materials and chalcogenides
- Diamond and Carbon-based Materials Research
- Crystal Structures and Properties
- Chemical and Physical Properties of Materials
- Advanced Memory and Neural Computing
- Quantum optics and atomic interactions
- Rare-earth and actinide compounds
- Ferroelectric and Negative Capacitance Devices
- High-pressure geophysics and materials
Donostia International Physics Center
2023-2025
St Petersburg University
2015-2024
Moscow Institute of Physics and Technology
2022-2024
Ikerbasque
2024
National University of Science and Technology
2022
Quantum states of matter combining non-trivial topology and magnetism attract a lot attention nowadays; the special focus is on magnetic topological insulators (MTIs) featuring quantum anomalous Hall axion insulator phases. Feasibility many novel phenomena that \emph{intrinsic} TIs may host depends crucially our ability to engineer efficiently tune their electronic structures. Here, using angle- spin-resolved photoemission spectroscopy along with \emph{ab initio} calculations we report large...
Abstract We study the surface crystalline and electronic structures of antiferromagnetic topological insulator MnBi 2 Te 4 using scanning tunneling microscopy/spectroscopy (STM/S), micro( μ )-laser angle-resolved photoemission spectroscopy (ARPES), density functional theory calculations. Our STM images reveal native point defects at that we identify as Bi antisites Mn substitutions. Bulk X-ray diffraction further evidences presence Mn-Bi intermixing. Overall, our characterizations suggest...
Using angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT), an experimental theoretical study of changes in the electronic structure (dispersion dependencies) corresponding modification energy band gap at Dirac point (DP) for topological insulator (TI) $$\textrm{Mn}_{1-x} \textrm{Ge}_x \textrm{Bi}_2 \textrm{Te}_4$$ have been carried out with gradual replacement magnetic Mn atoms by non-magnetic Ge when concentration latter was varied from 10% to 75%. It shown...
Graphene is one of the most promising materials for nanoelectronics owing to its unique Dirac cone-like dispersion electronic state and high mobility charge carriers. However, facilitate implementation graphene-based devices, an essential change structure, a creation band gap should controllably be done. Brought about by two fundamentally different mechanisms, sublattice symmetry breaking or induced strong spin-orbit interaction, appearance can drive graphene into narrow-gap semiconductor 2D...
In this work, we employed angle resolved photoemission spectroscopy (ARPES) to analyze the temperature dependent changes in electronic structure of first antiferromagnetic topological insulator MnBi2Te4 upon crossing Néel TN ≈ 25 K. We observed an exchange splitting bulk conduction band, which has a power law dependence on (1−T/T0)2β with onset T0 well matching measured TN. found evolution surface states integrated spectral weight vicinity Dirac point. Furthermore, additional quasi-2D state...
Abstract Modification of the gap at Dirac point (DP) in axion antiferromagnetic topological insulator $${\hbox {MnBi}}_2 {\hbox {Te}}_4$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mtext>MnBi</mml:mtext> <mml:mn>2</mml:mn> </mml:msub> <mml:mtext>Te</mml:mtext> <mml:mn>4</mml:mn> </mml:mrow> </mml:math> and its electronic spin structure have been studied by angle- spin-resolved photoemission spectroscopy (ARPES) under laser excitation various...
Recently discovered intrinsic antiferromagnetic topological insulator MnBi$_2$Te$_4$ presents an exciting platform for realization of the quantum anomalous Hall effect and a number related phenomena at elevated temperatures. An important characteristic making this material attractive applications is its predicted large magnetic gap Dirac point (DP). However, while early experimental measurements reported on DP gaps, recent studies claimed to observe gapless dispersion cone. Here, using...
Abstract The ability to finely tune the properties of magnetic topological insulators (TIs) is crucial for quantum electronics. We studied solid solutions with a general formula Ge x Mn 1-x Bi 2 Te 4 between two isostructural Z TIs, MnBi and nonmagnetic GeBi invariants 1;000 1;001, respectively. observed linear x-dependent properties, composition-independent pairwise exchange interactions, phase transitions (TPTs) topologically nontrivial phases semimetal state. TPTs are driven purely by...
The antiferromagnetic ordering that MnBi2Te4 shows makes it invariant with respect to the combination of time-reversal and primitive-lattice translation symmetries, giving rise its topologically nontrivial nature a number fundamental phenomena. At same time, possibility control electronic magnetic properties this system can provide new effective ways for application in devices. One approaches manipulate is partial substitution atoms compound non-magnetic elements, which inevitably affect...
A combined scanning tunneling microscopy, angle- and spin-resolved photoemission spectroscopy density functional theory study of graphene on Ir(1 1 1) intercalated with a well-ordered, full Pb monolayer is presented. Lead intercalation between reduces the coupling to metallic substrate in such way that its corrugation becomes negligible distortions linear dispersion largely disappear, while graphene's sublattice symmetry maintained it turns out be n-doped. Remarkably, spin–orbit splittings...
The electronic and spin structure of a graphene monolayer synthesized on Pt(111) has been investigated experimentally by angle- spin-resolved photoemission with different polarizations incident synchrotron radiation using density functional theory calculations. It is shown that despite the observed total quasifreestanding character dispersion $\ensuremath{\pi}$ state remarkable local distortions breaks in dispersions take place due to hybridization between Pt $d$ states. Corresponding...
A rich class of spintronics-relevant phenomena require implementation robust magnetism and/or strong spin–orbit coupling (SOC) to graphene, but both properties are completely alien it. Here, we for the first time experimentally demonstrate that a quasi-freestanding character, exchange splitting and giant SOC perfectly achievable in graphene at once. Using angle- spin-resolved photoemission spectroscopy, show Dirac state Au-intercalated on Co(0001) experiences (up 0.2 eV) while being by no...
One of the approaches to manipulate MnBi2Te4 properties is magnetic dilution, which inevitably affects interplay magnetism and band topology in system. In this work, we carried out angle-resolved photoemission spectroscopy (ARPES) measurements density functional theory (DFT) calculations for analysing changes electronic structure Mn1-xGexBi2Te4 that occur under parameter x variation. We consider two ways Mn/Ge substitution: (i) bulk doping whole system; (ii) surface first septuple layer. For...
CeTe$_3$ is a 2-dimensional (2D) Van der Waals (VdW) material with incommensurate charge density waves (CDW), extremely high transition temperature ($T_{CDW}$) and large momentum-dependent CDW gap that leaves significant portion of the Fermi surface intact. It also considered to be weak Kondo system, property unexpected for CDW, where each atomic site slightly different. Here, we study properties state in several RTe$_3$ (R rare earth) materials examine hybridization itinerant states...
High-resolution spin- and angle-resolved photoemission spectroscopy measurements were performed on the three-dimensional topological insulator Bi${}_{2}$Te${}_{2.4}$Se${}_{0.6}$, which is characterized by enhanced thermoelectric properties. The Fermi level position found to be located in bulk energy gap independent of temperature it stable over a long time. Spin textures Dirac-cone state at energies above below Dirac point as well Rashba-type valence band surface are observed agreement with...
Spin electronic structure of the Graphene/Pt interface has been investigated. A large induced spin-orbit splitting (∼80 meV) graphene π states with formation non-degenerated Dirac-cone spin at K¯-point Brillouin zone crossed spin-polarized Pt 5d Fermi level was found. We show that this can be used as a current source in spintronic devices. By theoretical estimations and micromagnetic modeling based on experimentally observed splitting, we demonstarte intrinsic magnetic field such might...
We investigated the magnetic properties of antiferromagnetic (AFM) topological insulator MnBi2Te4 with a partial substitution Mn atoms by non-magnetic elements (AIV = Ge, Pb, Sn). Samples various element concentrations (10–80%) were studied using SQUID magnetometry. The results demonstrate that, for all substitutes type ordering remains AFM, while Néel temperature (TN) and spin-flop transition field (HSF) decrease an increasing AIV Sn concentration. rate varies among elements, being highest...
The modification of the graphene spin structure is interest for novel possibilities application in spintronics. most exciting them demand not only high value spin-orbit splitting states, but non-Rashba behavior and spatial modulation interaction. In this work we study electronic on Ir(111) with intercalated Pt monolayer. interlayer does change $9.3\ifmmode\times\else\texttimes\fi{}9.3$ superlattice graphene, while Dirac cone becomes modified. It shown that Rashba $\ensuremath{\pi}$ state...
Possibility of in-plane and out-of-plane magnetization generated by synchrotron radiation (SR) in magnetically doped pristine topological insulators (TIs) is demonstrated studied angle-resolved photoemission spectroscopy. We show experimentally ab initio calculations how nonequal depopulation the Dirac cone (DC) states with opposite momenta V-doped TIs linearly polarized SR leads to hole-generated uncompensated spin accumulation followed SR-induced via spin-torque effect. Moreover,...
The non-volatile spin-orbit torque magnetic random access memory (SOT-MRAM) is a very attractive technology for near future computers because it has various advantages such as non-volatility, high density and scalability. In the present work we propose model of graphene recording device SOT-MRAM unit cell, consisting quasi-freestanding intercalated with Au an ultra-thin Pt layer sandwiched between tunnel junction. As result using claimed element, faster operation lower energy consumption...