Observation of topological surface state quantum Hall effect in an intrinsic three-dimensional topological insulator

Abstract

Abstract:A three-dimensional (3D) topological insulator (TI) is a quantum state of matter with a gapped insulating bulk yet a conducting surface hosting topologically-protected gapless surface states. One of the most distinct electronic transport signatures predicted for such topological surface states (TSS) is a well-defined half-integer quantum Hall effect (QHE) in a magnetic field, where the surface Hall conductivities become quantized in units of (1/2)e 2 /h (e being the electron charge, h the Planck constant) concomitant with vanishing resistance. Here, we observe well-developed QHE arising from TSS in an intrinsic TI of BiSbTeSe 2 . Our samples exhibit surface dominated conduction even close to room temperature, while the bulk conduction is negligible. At low temperatures and high magnetic fields perpendicular to the top and bottom surfaces, we observe well-developed integer quantized Hall plateaus, where the two parallel surfaces each contributing a half integer e 2 /h quantized Hall (QH) conductance, accompanied by vanishing longitudinal resistance. When the bottom surface is gated to match the top surface in carrier density, only odd integer QH plateaus are observed, representing a half-integer QHE of two degenerate Dirac gases. This system provides an excellent platform to pursue a plethora of exotic physics and novel device applications predicted for TIs, ranging from magnetic monopoles and Majorana particles to dissipationless electronics and fault-tolerant quantum computers.2

Quantum oscillations of the topological surface states in low carrier concentration crystals of Bi2−xSbxTe3Pan1, Никитин2, Wu3 et al. 2016Solid State Communications7100View full textAdd to dashboardCite

“…The appealing topological properties of BSTS, notably a tunable Dirac cone, were furthermore demonstrated by ARPES [16], STM and STS [17] and THz Time Domain Spectroscopy [18]. We remark that recently also stoichiometric BiSbTeSe 2 has become an attractive material to investigate topological surface states [19,20,21].…”

Metal-insulator transition and tunable Dirac-cone surface state in the topological insulatorTlBi1−xSbxTe2studied by angle-resolved photoemission

“…Angle-resolved photoemission spectroscopy (ARPES) study of BSTS has revealed a sign reversal of Dirac carriers while keeping insulating bulk [13]. Discovery of the BSTS system has accelerated the engineering of Dirac carriers and device applications [11,[14][15][16][17][18][19][20][21], as highlighted by the spin injection via spin-pumping technique [17], electrical detection of spin polarization [18], and realization of quantum Hall effect at high temperature [19]. To further realize exotic quantum phenomena and device applications in TIs, it is of particular importance to explore the new materials platform of bulk-insulating TIs, since the essential characteristics of bulk and surface, such as the bulk-band gap and the Dirac velocity, strongly depend on the material.…”

Theoretical models of Rashba spin splitting in asymmetric SrTiO3 -based heterostructures

“…Our results show a clear difference between the two descriptions that could be important for the interpretation of experimental results, in particular, as a consequence of the different resulting Fermi surfaces. Our findings will also have relevance to other 2D systems in correlated materials where spin-orbit coupling and Rashba effects are important, such as topological insulators, iridium oxides, and skyrmionic systems [6,[18][19][20][21].…”

“…The γ model has a very different, possibly unphysical, behavior in this range. Establishing the correct model to describe the Rashba spin splitting in oxide materials is important for a whole class of new 2D systems [18,19,21] in correlated materials.…”