Valence-band changes inSb2−xIn

Abstract

Valence band changes in Sb2-xInxTe3 and Sb2Te3-ySey by transprot and Shubnikovde Haas effect measurements Kulbachinskii, V.A.; Dashevski, Z.M.; Inoue, M.; Sasaki, M.; Negishi, H.; Gao, W.X.; Lostak, P.; Horak, J.; de Visser, A.

Substantial pressure effect on the resistivity and Curie temperature for the diluted magnetic semiconductor Sb2–xVxTe3

“…Given this similar effect, we suppose that it is primarily a characteristic of the host band structure that is responsible for the decrease in resistivity. If we adopt the model that holes from both an upper (high mobility) and lower (low mobility) valence band participate in the conduction [12], the pressure dependence of the band structure would be important when considering this reduction effect. In isostructural Bi 2 Te 3 , a similar reduction in ρ with pressure was interpreted by assuming the total number of free holes was constant and, upon application of pressure, heavy holes from the lower valence band filled the upper hole band as the energy separation between the valence band extrema increased [14].…”

“…A background free hole concentration of 1 × 10 20 cm -3 arising from native antisite defects is typical for pure Sb 2 Te 3 , and doping with vanadium does not alter the carrier concentration. The valence band of the host semiconductor is multi-valley [10,11] and there is evidence from Shubnikov-de Haas data that both an upper, light hole and lower, heavy hole band are populated for these high hole densities [12]. The pressure dependence of electrical resistivity in Sb 2 Te 3 [13] and isostructural Bi 2 Te 3 [14] has been investigated previously, and resistivity was found to be significantly reduced upon application of high pressures.…”

Transport and magnetic properties of the diluted magnetic semiconductors Sb1.98–xV0.02Crx Te3 and Sb1.984–yV0.016Mny Te3

“…It should be mentioned that due to the rather complicated band structure and the presence of two types of holes with different masses [17], the transport parameters presented in Table 3 may somewhat differ from the actual parameters. An estimate based on the parameters presented for Sb 2 Te 3 in paper [17] yields a contribution of heavy holes to R H of about 4% due to the fact that the mobility of light holes is by a factor ≈100 larger than that of heavy holes which are supposed to be the main mediator of interaction among localized spins.…”

Sum-Rule Constraints on the Surface State Conductance of Topological Insulators

“…Alternatively, we considered the case that the optical response arises from the bulk valence bands. Prior work has shown that the bulk valence band structure in the (Bi,Sb) 2 Te 3 system consist of of a light hole band (LHB) and heavy hole band (HHB) [3,14,15]. The effective masses of LHB and the HHB are 0.11m e and 1.0 m e respectively, and the top of the HHB is approximately 30 meV below the LHB [14,15].…”

“…Prior work has shown that the bulk valence band structure in the (Bi,Sb) 2 Te 3 system consist of of a light hole band (LHB) and heavy hole band (HHB) [3,14,15]. The effective masses of LHB and the HHB are 0.11m e and 1.0 m e respectively, and the top of the HHB is approximately 30 meV below the LHB [14,15]. To recover the correct value of D for this sample, E F would be 30 meV below the top of the LHB, However, this would yield an n 2D of 5 × 10 12 cm −2 , over a factor of two smaller than what was measured.…”