Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

A general structure model for Bi-Se phases using a superspace formalism

Lind, Hanna and Lidin, Sven LU (2003) In Solid State Sciences 5(1). p.47-57
Abstract

Solid-state synthesis in the Bi-Se system produced both commensurate and incommensurate phases of compositions ranging from Bi2Se3 to Bi4Se3, all crystallising in rhombohedral or trigonal layer structures. The a parameters are very similar for all phases but the c parameters vary irregularly between 10 and 100 Å. A general model for all these phases was developed, using single crystal X-ray diffraction and a four-dimensional superspace formalism. The 4D superspace group is P: R3: m11, with approximate cell parameters of a ≈ 4.2 Å and c ≈ 5.7 Å valid for all phases. The q vector value in this model, ranging from 1.70[001]* to 1.80[001]* is the only parameter that varies with the composition.... (More)

Solid-state synthesis in the Bi-Se system produced both commensurate and incommensurate phases of compositions ranging from Bi2Se3 to Bi4Se3, all crystallising in rhombohedral or trigonal layer structures. The a parameters are very similar for all phases but the c parameters vary irregularly between 10 and 100 Å. A general model for all these phases was developed, using single crystal X-ray diffraction and a four-dimensional superspace formalism. The 4D superspace group is P: R3: m11, with approximate cell parameters of a ≈ 4.2 Å and c ≈ 5.7 Å valid for all phases. The q vector value in this model, ranging from 1.70[001]* to 1.80[001]* is the only parameter that varies with the composition. Two different modelling options were developed for the structures. One of them was a single-atom refinement model consisting of harmonic modulation waves and the other was a two-atom model based on a displacive sawtooth modulation of the Se atom. Both models converged to low R-values (Rall < 0.07) and small residual electron density values for all phases. The q vector may be physically interpreted as arising from the average distance between homoatomic layers in the structures.

(Less)
Please use this url to cite or link to this publication:
author
and
publishing date
type
Contribution to journal
publication status
published
in
Solid State Sciences
volume
5
issue
1
pages
11 pages
publisher
Elsevier
external identifiers
  • scopus:0037274582
ISSN
1293-2558
DOI
10.1016/S1293-2558(02)00080-8
language
English
LU publication?
no
id
cf59fb76-da74-4442-95b0-fc1afe7aade8
date added to LUP
2019-04-08 15:34:19
date last changed
2022-01-31 18:51:58
@article{cf59fb76-da74-4442-95b0-fc1afe7aade8,
  abstract     = {{<p>Solid-state synthesis in the Bi-Se system produced both commensurate and incommensurate phases of compositions ranging from Bi<sub>2</sub>Se<sub>3</sub> to Bi<sub>4</sub>Se<sub>3</sub>, all crystallising in rhombohedral or trigonal layer structures. The a parameters are very similar for all phases but the c parameters vary irregularly between 10 and 100 Å. A general model for all these phases was developed, using single crystal X-ray diffraction and a four-dimensional superspace formalism. The 4D superspace group is P: R3: m11, with approximate cell parameters of a ≈ 4.2 Å and c ≈ 5.7 Å valid for all phases. The q vector value in this model, ranging from 1.70[001]* to 1.80[001]* is the only parameter that varies with the composition. Two different modelling options were developed for the structures. One of them was a single-atom refinement model consisting of harmonic modulation waves and the other was a two-atom model based on a displacive sawtooth modulation of the Se atom. Both models converged to low R-values (R<sub>all</sub> &lt; 0.07) and small residual electron density values for all phases. The q vector may be physically interpreted as arising from the average distance between homoatomic layers in the structures.</p>}},
  author       = {{Lind, Hanna and Lidin, Sven}},
  issn         = {{1293-2558}},
  language     = {{eng}},
  month        = {{01}},
  number       = {{1}},
  pages        = {{47--57}},
  publisher    = {{Elsevier}},
  series       = {{Solid State Sciences}},
  title        = {{A general structure model for Bi-Se phases using a superspace formalism}},
  url          = {{http://dx.doi.org/10.1016/S1293-2558(02)00080-8}},
  doi          = {{10.1016/S1293-2558(02)00080-8}},
  volume       = {{5}},
  year         = {{2003}},
}