Abstract
Helically spin-polarized Dirac fermions (HSDF) in protected topological surface states (TSS) are of high interest as a new state of quantum matter. In three-dimensional (3D) materials with TSS, electronic bulk states often mask the transport properties of HSDF. Recently, the high-field Hall resistance and low-field magnetoresistance indicate that the TSS may coexist with a layered two-dimensional electronic system (2DES). Here, we demonstrate quantum oscillations of the Hall resistance at temperatures up to 50 K in nominally undoped bulk Bi2Se3 with a high electron density n of about 2·1019 cm−3. From the angular and temperature dependence of the Hall resistance and the Shubnikov-de Haas oscillations we identify 3D and 2D contributions to transport. Angular resolved photoemission spectroscopy proves the existence of TSS. We present a model for Bi2Se3 and suggest that the coexistence of TSS and 2D layered transport stabilizes the quantum oscillations of the Hall resistance.
Highlights
Among the new material class of topological insulators (TI), the chalcogenide semiconductor Bi2Se3 has been long subject to intense investigations due to its potential integration in room temperature applications, such as dissipationless electronics and spintronics devices[1,2,3,4]
High-resolution angle resolved photoemission spectroscopy (ARPES) dispersions measured at a temperature of 12 K for two representative photon energies of hν = 16 eV and 21 eV are shown in Fig. 1a and b, respectively
Consistent with the direct nature of the gap, we find the bulk conduction band (BCB) minimum (≈Γ-point of the bulk Brillouin zone (BBZ)) at a binding energy of ∼0.154 eV, while the bulk valence band (BVB) maximum is at ∼0.452 eV
Summary
Among the new material class of topological insulators (TI), the chalcogenide semiconductor Bi2Se3 has been long subject to intense investigations due to its potential integration in room temperature applications, such as dissipationless electronics and spintronics devices[1,2,3,4]. In this work we demonstrate that the quantum oscillations of the Hall resistance Rxy in high-purity, nominally undoped Bi2Se3 single crystals with a carrier density of n ≈ 2 ⋅ 1019 cm−3 persists up to high temperatures. The quantum oscillations in Rxy scale with the sample thickness, strongly indicating 2D layered transport. These findings stand out because the Bi2Se3 samples investigated here have a lower carrier mobility μ of about 600 cm2/(Vs) than materials hosting a typical 2D Fermi gas[19,20,21,22] or 3D Fermi gas[23,24,25] showing QHE. We discuss the conditions of the QHE below in detail and present a model for the coexistence of 3D bulk, 2D layered and TSS transport
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
