A5055687540- Topological Materials and Phenomena
- Quantum and electron transport phenomena
- Advanced Semiconductor Detectors and Materials
- Graphene research and applications
- Semiconductor Quantum Structures and Devices
- 2D Materials and Applications
- Physics of Superconductivity and Magnetism
- Terahertz technology and applications
- Electronic and Structural Properties of Oxides
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum many-body systems
- Photonic and Optical Devices
- Photorefractive and Nonlinear Optics
- Magnetic properties of thin films
- Advancements in Semiconductor Devices and Circuit Design
- Magnetic Field Sensors Techniques
- Diamond and Carbon-based Materials Research
- Molecular Junctions and Nanostructures
- Superconducting Materials and Applications
- Nuclear Physics and Applications
- Strong Light-Matter Interactions
- Advanced Chemical Physics Studies
- Particle accelerators and beam dynamics
- Quantum Mechanics and Non-Hermitian Physics
- Neural Networks and Applications
Université de Montpellier
2016-2025
Laboratoire Charles Coulomb
2016-2025
Centre National de la Recherche Scientifique
2013-2024
University of Würzburg
2024
Moscow State University
2023
Institute of High Pressure Physics
2020-2022
Polish Academy of Sciences
2020-2022
Lomonosov Moscow State University
2022
Laboratoire National des Champs Magnétiques Intenses
2011-2019
Institute for Physics of Microstructures
2010-2019
It has recently been shown that the electronic states in bulk gapless HgCdTe offer another realization of pseudo-relativistic three-dimensional particles a condensed matter system. These single valley relativistic states, referred to as massless Kane fermions, cannot be described by any other well-known particles. Furthermore, band structure can continuously tailored modifying either cadmium content or temperature. At critical concentration temperature, bandgap, Eg, collapses system...
We present theoretical investigations of pressure and temperature driven phase transitions in HgTe quantum wells grown on CdTe buffer. Using the 8-band \textbf{k$\cdot$p} Hamiltonian we calculate evolution energy band structure at different well width with hydrostatic up to 20 kBar ranging 300 K. In particular, show that addition temperature, tuning allows drive between semimetal, insulator topological phases. Our realistic calculations reveal inversion under may be accompanied by non-local...
Due to their specific physical properties, HgCdTe-based heterostructures are expected play an important role in terahertz photonic systems. Here, focusing on gated devices presenting inverted band ordering, we evidence enhancement of the photoconductive response close charge neutrality point and at magnetic field driven topological phase transition. We also show ability these be used as imagers. Regarding emitters, present results stimulated emission HgCdTe conventional semiconductor state...
We report a direct observation of temperature-induced topological phase transition between the trivial and insulator states in an HgTe quantum well. By using gated Hall bar device, we measure represent Landau levels fan charts at different temperatures, follow temperature evolution peculiar pair "zero-mode" levels, which split from edge electronlike holelike subbands. Their crossing critical magnetic field Bc is characteristic inverted band structure measuring dependence Bc, directly extract...
We report on the temperature-dependent magnetospectroscopy of two HgTe/CdHgTe quantum wells below and above critical well thickness ${d}_{c}$. Our results, obtained in magnetic fields up to 16 T s temperature range from 2 150 K, clearly indicate a change band-gap energy with temperature. A wider than ${d}_{c}$ evidences temperature-driven transition topological insulator semiconductor phases. At 90 merging inter- intraband transitions weak specifies formation gapless state, revealing...
Abstract HgTe quantum wells possess remarkable physical properties as for instance the spin Hall state and “single-valley” analog of graphene, depending on their layer thicknesses barrier composition. However, double yet contain more fascinating still unrevealed features. Here we report study phase transitions in tunnel-coupled layers separated by CdTe barrier. We demonstrate that this system has a 3/2 pseudo degree freedom, which features number particular associated with spin-dependent...
We report intense terahertz electroluminescence from Dirac-Landau polaritons, representing a major step toward achieving stimulated cyclotron emission and polariton-based lasers. By strongly coupling the transitions of two-dimensional Dirac fermions in HgTe quantum wells with optical cavity modes, we observe efficient near lasing threshold. This work demonstrates that polariton condensation, process bypasses need for electronic population inversion, can significantly reduce threshold...
The quantum spin Hall insulator (QSHI) state has been demonstrated in two semiconductor systems - HgTe/CdTe wells (QWs) and InAs/GaSb QW bilayers. Unlike the QWs, inverted band gap bilayers does not open at $\Gamma$ point of Brillouin zone, preventing realization massless Dirac fermions. Here, we propose a new class based on InAs/Ga(In)Sb multilayers, hosting QSHI state, graphene-like phase bilayer graphene analogue, depending their layer thicknesses geometry. novel structures can reach up...
We propose a minimal effective two-dimensional Hamiltonian for HgTe/CdHgTe quantum wells (QWs) describing the side maxima of first valence subband. By using Hamiltonian, we explore picture helical edge states in tensile and compressively strained HgTe QWs. show that both dispersion probability density can differ significantly from those predicted by Bernevig-Hughes-Zhang (BHZ) model. Our results pave way towards further theoretical investigations HgTe-based spin Hall insulators with direct...
We report on temperature-dependent terahertz spectroscopy of a three-layer InAs/GaSb/InAs quantum well (QW) with inverted-band structure. The interband optical transitions, measured up to 16 T at different temperatures by Landau-level magnetospectroscopy, demonstrate the structure QW. photoluminescence allows us directly extract gap in vicinity $\mathrm{\ensuremath{\Gamma}}$ point Brillouin zone. Our results experimentally that QWs is temperature independent and exceeds four times maximum...
We report on magnetospectroscopy of HgTe quantum wells in magnetic fields up to 45 T a temperature range from 4.2 185 K. observe intra- and inter-band transitions zero-mode Landau levels, which split the bottom conduction upper valence sub-bands merge under applied field. To describe experimental results, realistic temperature-dependent calculations levels have been performed. show that although our samples are topological insulators at low temperatures only, signature such phase persists...
Materials with linear electronic dispersion often feature high carrier mobilities and unusually strong nonlinear optical interactions. In this work, we investigate the (THz) dynamics of one such material, HgCdTe, an band heavily dependent on both temperature stoichiometry. We show how gap, concentration shape together determine response system. At low temperatures, generation from Zener tunneling dominates a reduction in overall transmission. room temperature, quasiballistic drive largest...
We report on the study of exchange enhancement g-factor in two-dimensional (2D) electron gas n-type narrow-gap semiconductor heterostructures. Our approach is based eight-band k⋅p Hamiltonian and takes into account band nonparabolicity, lattice deformation, spin–orbit coupling Landau level broadening δ-correlated random potential model. Using 'screened' Hartree–Fock approximation we demonstrate that not only shows maxima at odd values filling factors but, due to conduction persists even...
We report on the clear evidence of massless Dirac fermions in two-dimensional system based III-V semiconductors. Using a gated Hall bar made three-layer InAs/GaSb/InAs quantum well, we restore Landau levels fan chart by magnetotransport and unequivocally demonstrate gapless state our sample. Measurements cyclotron resonance at different electron concentrations directly indicate linear band crossing $\Gamma$ point Brillouin zone. Analysis experimental data within analytical Dirac-like...
Abstract HgTe quantum wells (QWs) are two-dimensional semiconductor systems that change their properties at the critical thickness d c , corresponding to band inversion and topological phase transition. The motivation of this work was study magnetotransport QWs with approaching examine them as potential candidates for Hall effect (QHE) resistance standards. We show in case > (inverted QWs), quantization is influenced by coexistence helical edge states QHE chiral states. However, ≈ where...
We report on sub-terahertz photoconductivity under the magnetic field of a two dimensional topological insulator based HgTe quantum wells. perform detailed visualization Landau levels by means measured at different gate voltages. This technique allows one to determine critical field, corresponding phase transition from inverted normal band structure, even in almost gapless samples. The comparison with realistic calculations reveals smaller role bulk inversion asymmetry wells than it was...