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Title: Density functional theory calculations of the turbostratically disordered compound [(SnSe)1+y]m(VSe2)n

Among composite materials that layer constituent substances of nanoscale thicknesses, [(SnSe)1+y ]m(VSe2)n emerges as an example where the constituents retain incommensurate lattice structures. Perpendicular to the stacking direction, the system exhibits random translations and random rotations on average, i.e., turbostratic disorder, with local regions showing twelvefold diffraction patterns. Earlier theoretical work on these structures showed that combining density functional theory with an empirical treatment of the van der Waals interaction gave structural parameters in good agreement with experiment, but no attempt was made to examine the relative orientations. Here we approximate the extended system with one extended constituent and one finite constituent, which allows the treatment of all relative orientations on equal footing. Furthermore, the calculations show how the twelvefold periodicity follows from how the ions of the SnSe layer lock in with favored positions relative to the VSe2 layer, and the associated energy scale supports arguments for the overall turbostratic disorder.
Authors:
 [1] ;  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. of Oregon, Eugene, OR (United States)
Publication Date:
OSTI Identifier:
1224054
Report Number(s):
LA-UR--15-21402
Journal ID: ISSN 1098-0121; PRBMDO
Grant/Contract Number:
AC52-06NA25396; LDRD-DR 20140025; DMR-1266217
Type:
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 91; Journal Issue: 14; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY