Quantum Oscillations and Hall Anomaly of Surface States in the Topological Insulator Bi ₂ Te ₃

Abstract

Topological insulators are insulating materials that display massless, Dirac-like surface states in which the electrons have only one spin degree of freedom on each surface. These states have been imaged by photoemission, but little information on their transport parameters, for example, mobility, is available. We report the observation of Shubnikov-de Haas oscillations arising from the surface states in nonmetallic crystals of Bi(2)Te(3). In addition, we uncovered a Hall anomaly in weak fields, which enables the surface current to be seen directly. Both experiments yield a surface mobility (9000 to 10,000 centimeter(2) per volt-second) that is substantially higher than in the bulk. The Fermi velocity of 4 x 10(5) meters per second obtained from these transport experiments agrees with angle-resolved photoemission experiments.

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

“…At the same time, it may give direct access to the topological nature of the surface states via the geometric phase (Berry phase) [24,25] of the quantum oscillations. Therefore, the SdH effect in TIs has received ample attention in the literature, notably through experiments carried out on bulk crystals of Bi 2 Te 3 , Bi 2 Se 3 and Bi 2 Te 2 Se [12,11,26,27,28]. In addition, the SdH effect was reported for nonstochiometric BSTS (x, y)=(0.50,1.3) bulk crystals [29] and nanoflakes [30].…”

“…This seriously hampers the study of topological surface states in transport experiments, as well as potential device applications based on spin and charge transport. In order to solve this problem several research directions have been pursued, among which charge carrier doping [11,12], thin film engineering and electrostatic gating [13,14]. Yet another route was promoted by Ren et al [15], namely to approach the intrinsic topological insulator regime by optimizing the Bi 2−x Sb x Te 3−y Se y (in short BSTS) composition.…”

Electrical Detection of Spin-Polarized Surface States Conduction in (Bi0.53Sb0.47)2Te3 Topological Insulator

“…This is smaller than the theoretical predication of about 50% spin polarization for the 3D TI surface states from first-principle calculations. 21 Such deviation can be probably attributed to that the dimension of the top surface in our device (in micron scale) is much larger than the typical mean-free path and phase coherence length (tens to hundreds nanometers, see Supporting Information S10), 17,18,37 hence the carrier transport through the surface states suffers from considerable scatterings. Another possible reason could be the overestimation of the spin detection efficiency in the nonideal Co/Al 2 O 3 tunneling contact, considering that the (Bi 0.53 Sb 0.47 ) 2 Te 3 surface has a terracelike morphology.…”

Granularity Controlled Nonsaturating Linear Magnetoresistance in Topological Insulator Bi2Te3 Films

“…14,15 In the last few years, the rapid expansion of the emerging field of topological insulators (TIs) has again stimulated intensive research on the MR in these topological materials with non-trivial zero-gap Dirac-like surface states. [16][17][18][19][20][21][22][23][24][25][26] After the initial discovery of a LMR together with the two-dimensional (2D) quantum oscillations of MR from the surface states, 16,17 many further experiments confirmed the existence of LMR in TI materials. [18][19][20][21][22][23][24][25][26] 18,22 Utilizing tilted magnetic field measurement, the linear MR of single crystalline TI in perpendicular field was attributed to the 2D gapless topological surface states and of quantum origin.…”