A general structure model for Bi-Se phases using a superspace formalism
(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)
- author
- Lind, Hanna and Lidin, Sven LU
- publishing date
- 2003-01-01
- 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> < 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}}, }