Temperature-driven single-valley Dirac fermions in HgTe quantum wells

Abstract

We report on temperature-dependent magnetospectroscopy of two HgTe/CdHgTe quantum wells below and above the critical well thickness $d_c$. Our results, obtained in magnetic fields up to 16 T and temperature range from 2 K to 150 K, clearly indicate a change of the band-gap energy with temperature. The quantum well wider than $d_c$ evidences a temperature-driven transition from topological insulator to semiconductor phases. At the critical temperature of 90 K, the merging of inter- and intra-band transitions in weak magnetic fields clearly specifies the formation of gapless state, revealing the appearance of single-valley massless Dirac fermions with velocity of $5.6\times 10^5$ m$\times$s${}^{-1}$. For both quantum wells, the energies extracted from experimental data are in good agreement with calculations on the basis of the 8-band Kane Hamiltonian with temperature-dependent parameters.

arXiv comment5 pages, 3 figures and Supplemental Materials (4 pages)

References in corpus (19)

• Two-Dimensional Gas of Massless Dirac Fermions in Graphene
• Topological Insulators
• Experimental Observation of Quantum Hall Effect and Berry's Phase in Graphene
• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Discovery of a Weyl Fermion Semimetal and Topological Fermi Arcs
• Dirac materials
• The Quantum Spin Hall Effect: Theory and Experiment
• Single valley Dirac fermions in zero-gap HgTe quantum wells
• 3D massless Kane fermions observed in a zinc-blende crystal
• Temperature-driven massless Kane fermions in HgCdTe crystals: verification of universal velocity and rest-mass description
• Pressure and temperature driven phase transitions in HgTe quantum wells
• Split Dirac cones in HgTe/CdTe quantum wells due to symmetry-enforced level anticrossing at interfaces
• Fine structure of "zero-mode" Landau levels in HgTe/HgCdTe quantum wells
• Phase transitions in two tunnel-coupled HgTe quantum wells. Bilayer graphene analogy and beyond
• Temperature-driven transition from a semiconductor to a topological insulator
• Design principles for HgTe based topological insulator devices
• Cyclotron resonance of single valley Dirac fermions in gapless HgTe quantum well
• Temperature-dependent magnetospectroscopy of HgTe quantum wells

Cited by in corpus (21)

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• Large gap quantum spin Hall insulator, massless Dirac fermions and bilayer graphene analogue in InAs/Ga(In)Sb heterostructures
• Realistic picture of helical edge states in HgTe quantum wells
• Topological insulators based on HgTe
• Massless Dirac fermions in III-V semiconductor quantum wells
• Perspectives of HgTe Topological Insulators for Quantum Hall Metrology
• Landau level spectroscopy of valence bands in HgTe quantum wells: Effects of symmetry lowering
• Unconventional Reentrant Quantum Hall Effect in a HgTe/CdHgTe Double Quantum Well
• Terahertz cyclotron emission from two-dimensional Dirac fermions
• Disorder-induced phase transition in Dirac systems beyond the linear approximation
• Avoided level crossing at the magnetic field induced topological phase transition due to spin-orbital mixing
• Many-particle effects in optical transitions from zero-mode Landau levels in HgTe quantum wells
• Multi-probe analysis to separate edge currents from bulk currents in quantum spin Hall insulators and to analyze their temperature dependence
• Disorder-induced phase transitions in double HgTe quantum wells
• Quasiparticle picture of topological phase transitions induced by interactions
• Bleaching of the Terahertz Magneto-Photogalvanic Effect in CdHgTe Crystals with Kane Fermions
• Gate tunable terahertz cyclotron emission from two-dimensional Dirac fermions
• Electron-hole collision-limited resistance of gapped graphene
• Large inverted band-gap in strained three-layer InAs/GaInSb quantum wells
• Many-particle hybridization of optical transitions from zero-mode Landau levels in HgTe quantum wells
• Relativistic collapse of Landau levels of Kane fermions in crossed electric and magnetic fields