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Title: Sn 2Se 3: A conducting crystalline mixed valent phase change memory compound

Thin film Sn 2Se 3 is a promising new phase change memory material with a very high resistance contrast between insulating amorphous and conducting crystalline phases. In this paper, we identify the structure of the Sn 2Se 3 crystalline phase using ab initio evolutionary structure search and report its properties. We find a structure based on Sn-Se ribbons with clear disproportionation of Sn into Sn(II) and Sn(IV) sites, similar to Sn 2S 3. The energy is only 9 meV/atom above the tie line between SnSe and SnSe 2. Sn charge disproportionation is only marginally favored in this selenide, in contrast to sulfides. This leads to a semimetallic rather than semiconducting behavior. Finally, these findings, marginal stability of the crystalline phase and conducting character and close competition of disproportionated and non-disproportionated structures, are important for understanding the behavior of Sn 2Se 3 as a phase change memory material, specifically the fast low energy, the low temperature switching, and the high resistance contrast.
Authors:
 [1] ;  [2] ; ORCiD logo [3] ;  [3] ;  [3] ; ORCiD logo [2]
  1. Jilin Univ., Changchun (China). College of Materials Science and Engineering. Key Lab. of Automobile Materials of MOE; Univ. of Missouri, Columbia, MO (United States). Dept. of Physics and Astronomy
  2. Univ. of Missouri, Columbia, MO (United States). Dept. of Physics and Astronomy
  3. Jilin Univ., Changchun (China). College of Materials Science and Engineering. Key Lab. of Automobile Materials of MOE
Publication Date:
Grant/Contract Number:
SC0014607
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 121; Journal Issue: 22; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of Missouri, Columbia, MO (United States); Jilin Univ., Changchun (China)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); China Scholarship Council (CSC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1473914
Alternate Identifier(s):
OSTI ID: 1366566