Quantum Hall effect and Landau levels in the 3D topological insulator HgTe

Abstract

We review low and high field magnetotransport in 80 nm-thick strained HgTe, a material that belongs to the class of strong three-dimensional topological insulators. Utilizing a top gate, the Fermi level can be tuned from the valence band via the Dirac surface states into the conduction band and allows studying Landau quantization in situations where different species of charge carriers contribute to magnetotransport. Landau fan charts, mapping the conductivity ${\sigma }_{xx}(V_g,B)$ in the whole magnetic field - gate voltage range, can be divided into six areas, depending on the state of the participating carrier species. Key findings are: (i) the interplay of bulk holes (spin-degenerate) and Dirac surface electrons (non-degenerate), coexisting for $E_F$ in the valence band, leads to a periodic switching between odd and even filling factors and thus odd and even quantized Hall voltage values. (ii) A similar though less pronounced behavior we found for coexisting Dirac surface and conduction band electrons. (iii) In the bulk gap, quantized Dirac electrons on the top-surface coexist at lower B with non-quantized ones on the bottom side, giving rise to quantum Hall plateau values depending - for a given filling factor - on the magnetic field strength. In stronger $B$ fields, Landau level separation increases, charge transfer between different carrier species becomes energetically favorable and leads to the formation of a global (i.e. involving top and bottom surface) quantum Hall state. Simulations using the simplest possible theoretical approach are in line with the basic experimental findings, describing correctly the central features of the transitions from classical to quantum transport in the respective areas of our multicomponent charge carrier system.

arXiv comment12 pages, 6 figures

References in corpus (22)

• Topological Insulators
• Topological insulators and superconductors
• Topological Insulators with Inversion Symmetry
• Unconventional quantum Hall effect and Berry's phase of 2pi in bilayer graphene
• Topological Insulator Materials
• Quantum Hall Effect from the Topological Surface States of Strained Bulk HgTe
• Observation of topological surface state quantum Hall effect in an intrinsic three-dimensional topological insulator
• Spin and valley quantum Hall ferromagnetism in graphene
• The zero-energy state in graphene in a high magnetic field
• Quantum Hall Effect on Top and Bottom Surface States of Topological Insulator (Bi1-xSbx)2Te3 Films
• Gap opening in the zeroth Landau level of graphene
• Transport properties of a 3D topological insulator based on a strained high mobility HgTe film
• Cyclotron Resonance Assisted Photocurrents in Surface States of a 3D Topological Insulator Based on a Strained High Mobility HgTe Film
• Probing Spin Helical Surface States in Topological HgTe Nanowires
• Probing quantum capacitance in a 3D topological insulator
• The valence band energy spectrum of HgTe quantum wells with inverted band structures
• Ballistic geometric resistance resonances in a single surface of a topological insulator
• Landau Level Anticrossing Manifestations in the Phase Diagram Topology of a Two Subband System
• Ab initio study of topological surface states of strained HgTe
• Robust helical edge transport at $\nu =0$ quantum Hall state
• Phase Slips and Parity Jumps in Quantum Oscillations of Inverted InAs/GaSb Quantum Wells
• Revealing topological Dirac fermions at the surface of strained HgTe thin films via Quantum Hall transport spectroscopy

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• Bilinear magnetoresistance in HgTe topological insulator: opposite signs at opposite interfaces demonstrated by gate control
• Terahertz photoresistivity of a high-mobility 3D topological insulator based on a strained HgTe film
• Electron-hole scattering limited transport of Dirac fermions in a topological insulator
• Transport properties of a 1000-nm HgTe film: the interplay of surface and bulk carriers
• Transformation of an energy spectrum and wave functions in the crossover from two- to three-dimensional topological insulator in HgTe quantum wells: long and thorny way
• Thermoelectric transport in a three-dimensional HgTe topological insulator
• Anomalous conductance steps in three-dimensional topological insulator HgTe-based quantum point contacts
• Self-Consistent Model for Gate Control of Narrow-, Broken-, and Inverted-Gap (Topological) Heterostructures