Title
|
|
|
|
Homologous series of layered structures in binary and ternary Bi-Sb-Te-Se systems : ab initio study
| |
Author
|
|
|
|
| |
Abstract
|
|
|
|
In order to account explicitly for the existence of long-periodic layered structures and the strong structural relaxations in the most common binary and ternary alloys of the Bi-Sb-Te-Se system, we have developed a one-dimensional cluster expansion (CE) based on first-principles electronic structure calculations, which accounts for the Bi and Sb bilayer formation. Excellent interlayer distances are obtained with a van der Waals density functional. It is shown that a CE solely based on pair interactions is sufficient to provide an accurate description of the ground-state energies of Bi-Sb-Te-Se binary and ternary systems without making the data set of ab initio calculated structures unreasonably large. For the binary alloys A1−xQx (A=Sb, Bi; Q=Te, Se), a ternary CE yields an almost continuous series of (meta)stable structures consisting of consecutive A bilayers next to consecutive A2Q3 for 00.6, the binary alloy segregates into pure Q and A2Q3. The Bi-Sb system is described by a quaternary CE and is found to be an ideal solid solution stabilized by entropic effects at T≠0 K but with an ordered structure of alternating Bi and Sb layers for x=0.5 at T=0 K. A quintuple CE is used for the ternary Bi-Sb-Te system, where stable ternary layered compounds with an arbitrary stacking of Sb2Te3, Bi2Te3, and Te-Bi-Te-Sb-Te quintuple units are found, optionally separated by mixed Bi/Sb bilayers. Electronic properties of the stable compounds were studied taking spin-orbit coupling into account. |
| |
Language
|
|
|
|
English
| |
Source (journal)
|
|
|
|
Physical review : B : condensed matter and materials physics. - Lancaster, Pa, 1998 - 2015
| |
Publication
|
|
|
|
Lancaster, Pa
:
2014
| |
ISSN
|
|
|
|
1098-0121
[print]
1550-235X
[online]
| |
DOI
|
|
|
|
10.1103/PHYSREVB.89.054106
| |
Volume/pages
|
|
|
|
89
:5
(2014)
, p. 1-9
| |
Article Reference
|
|
|
|
054106
| |
ISI
|
|
|
|
000332420900001
| |
Medium
|
|
|
|
E-only publicatie
| |
Full text (Publisher's DOI)
|
|
|
|
| |
Full text (open access)
|
|
|
|
| |
|