Experimental study of the valence band ofBi2Se3

Abstract

The valence band of Bi 2 Se 3 is investigated by measuring Shubnikov-de Haas effect as well as galvanomagnetic and thermoelectric transport. At low hole concentration, the hole Fermi surface is closed and box-like, but at higher carrier concentrations it develops tube-like extensions that are open, in general agreement with our theoretical calculations. However, the experimentally determined density-of-states effective mass is smaller than densityfunctional theory calculations predict; while we cannot give a definitive explanation for this, we suspect that the theory may lack sufficient precision to compute room-temperature transport properties, such as the thermopower, in solids with interlayer Van der Waals bonds.2

Hole Fermi surface inBi2Se3probed by quantum oscillations

“…This value is consistent with the values obtained in a higher (but overlapping) energy range. 13 A non-trivial field dependence was observed as the magnetic field was increased, 21 but is beyond the scope of the present paper where we aim at characterizing the (fieldindependent) hole Fermi surface. From the frequency F of the quantum oscillations discussed in the previous section, one can deduce the extremal Fermi surface crosssection in the momentum space, CS = πk 2 F (where k F is the Fermi wave vector), given by CS = 2πeF/ .…”

Two-band model interpretation of the p- to n-transition in ternary tetradymite topological insulators

“…The mobility of holes is expected to decrease upon alloying with Se. For both Bi 2 Te 3 and Bi 2 Se 3 the valence band structure is complex [26,27]. Different valleys in both the conduction and the valence bands may contribute to conduction upon alloying [16].…”

Surface and interface states of Bi2Se3 thin films investigated by optical second-harmonic generation and terahertz emission

“…4(b)). 30 When the photo-carriers are accelerated in upward (downward) band bending, the direction of the transient dipole, or equivalently the phase of the THz wave, will be the same as (opposite to) that formed in InAs. 31 Therefore, we determined the surface electronic states by examining the details of the THz field profiles, namely, the phase and amplitude of the emitted THz wave.…”