Quantum Interference in Macroscopic Crystals of NonmetallicBi2Se3

Abstract

Photoemission experiments have shown that Bi2Se3 is a topological insulator. By controlled doping, we have obtained crystals of Bi2Se3 with nonmetallic conduction. At low temperatures, we uncover a novel type of magnetofingerprint signal which involves the spin degrees of freedom. Given the mm-sized crystals, the observed amplitude is 200-500x larger than expected from universal conductance fluctuations. The results point to very long phase-breaking lengths in an unusual conductance channel in these nonmetallic samples. We discuss the nature of the in-gap conducting states and their relation to the topological surface states.

Indications of surface-dominated transport in single crystalline nanoflake devices of topological insulator Bi1.5Sb0.5TeXia1, Ren2, Sulaev3 et al. 2013Phys. Rev. B137181572View 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 .…”

Topologicalp-njunction

“…The single Dirac cone on the Bi 2 X 3 (X = Se and Te) surface [8][9][10] can be viewed as one quarter of graphene 11 , and it is predicted to exhibit half-Integer quantum Hall effect 7 , which is a unique property of a time-reversal symmetry-breaking surface and is determined by the bulk topology. Extensive efforts such as chemical doping and electric gating have been made to achieve the purely conducting surface in transport on topological insulators [12][13][14][15][16][17][18][19] , however, they are hindered by intrinsic defects in the materials where Bi 2 X 3 is the significant bulk conduction.…”

Fabrication of Graphene/Bi2Se3/Graphene heterostructure without the surface oxidation of Bi2Se3

“…Layer-structured Bi 2 Se 3 materials may be applied for the future spintronics and quantum computing devices due to large ratio of surface-to-volume, thus it is urgent to synthesize high-quality Bi 2 Se 3 with defined sizes [2][3][4]. Various methods have been tried to fabricate Bi 2 Se 3 thin film, such as molecular beam epitaxial (MBE) [5,6], solvothermal synthesis [7], mechanical exfoliation [8], metalorganic chemical vapor deposition (MOCVD) [9] and chemical vapor deposition (CVD) [10][11][12][13]. Compared with other methods, CVD is an inexpensive and effective strategy to obtain Bi 2 Se 3 materials.…”