Weak antilocalization and conductance fluctuation in a submicrometer-sized wire of epitaxial Bi2Se3

Coherent topological transport on the surface of Bi2Se3

“…In contrast to previous studies of WAL in TI thin films [15][16][17][18][19][20][21][22] where strong surface to bulk scattering dominates inter-channel coupling, here we report WAL measurements in gate-tuned, bulkinsulating Bi 2 Se 3 thin films where we expect negligible surfacebulk scattering. We find that the WAL behaviour in TI regime is governed by the ratio of t j to the inter-surface tunnelling time t t ¼ h/2D, where h is Planck's constant and D is the hybridization gap induced by inter-surface tunnelling 12,14 .…”

“…S4 and Supplementary Note 4), which limits temperature as a parameter to control interlayer coherence. The weak temperature dependence of t j is observed elsewhere 21 but not understood, though it suggests an extrinsic mechanism. If the lowtemperature decoherence can be improved, it may be possible to explore temperature-driven coherent coupling/decoupling of the TI surfaces.…”

“…Ds(H) in our devices include a moderate contribution from (universal) conductance fluctuations (Fig. 2), as commonly observed in micro-fabricated Bi 2 Se 3 devices 16,21 ; the fluctuations are reduced by fitting to equation (1) over a large field range (0 T, 0.8 T). At the upper end of this field range, the magnetic length l B ¼ (:/eH) 1/2 becomes comparable to the electronic mean free path l mfp , approaching the regime where equation (1) may not be valid.…”

Weak antilocalization in topological insulator Bi2Te3microflakes

“…On the other hand, the WAL effect in BT-15 is obscured by the relatively large universal conductance fluctuations (UCFs). [30][31][32] In the rest of this paper, we shall thus focus our analysis of the WAL effect only on the BT-24 sample. It is, however, worth noting in passing that the UCF signals do allow us to extract the electron dephasing length L ϕ (T ).…”

Indications of surface-dominated transport in single crystalline nanoflake devices of topological insulator Bi1.5Sb0.5TeXia1, Ren2, Sulaev3 et al. 2013Phys. Rev. B136181572View full textAdd to dashboardCite

“…Realizing surface dominated transport in current topological insulator systems is still a challenge despite extensive efforts involving chemical doping 22,[33][34][35][36][37][38][39] , thin film or nanostructure fabricating [25][26][27][28][29][30][31][32] and electrical gating 21,26,32 .…”