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Title: Charge Density Wave and Narrow Energy Gap at Room Temperature in 2D Pb 3–xSb 1+xS 4Te 2-δ with Square Te Sheets

We report a new two-dimensional compound Pb 3–xSb 1+xS 4Te 2-δ has a charge density wave (CDW) at room temperature. The CDW is incommensurate with q-vector of 0.248(6)a* + 0.246(8)b* + 0.387(9)c* for x = 0.29(2) and d = 0.37(3) due to positional and occupational long range ordering of Te atoms in the sheets. The modulated structure was refined from the single crystal X-ray diffraction data with a superspace group P$$\bar{1}$$(αβγ)0 using (3 + 1)-dimensional crystallography. The resistivity increases with decreasing temperature, suggesting semiconducting behavior. The transition temperature (T CDW) of the CDW is ~ 345 K above which the Te square sheets become disordered with no q-vector. Lastly, first-principles density functional theory calculations on the undistorted structure and an approximate commensurate supercell reveal that the gap is due to the structure modulation.
Authors:
ORCiD logo [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [2] ;  [3] ; ORCiD logo [1]
  1. Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
  2. Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Physics
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 139; Journal Issue: 32; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Emergent Superconductivity (CES)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; Charge density wave; Incommensurate super-lattice; Semiconductor
OSTI Identifier:
1393841