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Title: Internal and external thermal expansions of wurtzite ZnO from first principles

Abstract

Many crystals contain “internal” structural parameters not completely constrained by symmetry. These vary with temperature T, similar to the variation of “external” structural parameters that describe the unit cell. The term “thermal expansion” most often refers to the external parameters, which are more easily and accurately measured. Here we use “thermal expansion” to mean both external and internal parameters. Internal thermal expansion impacts a wide range of applications, but has been given less attention. In this study, the thermal expansion behavior of wurtzite ZnO is studied from first principles with the generalized Grüneisen theory in the framework of quasi-harmonic approximation (QHA). Negative external thermal expansions are found below the temperature of 150 K. We demonstrate that the so-called “zero static internal stress approximation” (ZSISA) gives the correct external but incorrect internal thermal expansions, due to the neglect of the clamped-lattice internal contribution contained in the generalized Grüneisen theory. Although accurate at low T, at higher T the QHA may need to be supplemented by higher order anharmonic corrections.

Authors:
ORCiD logo [1];  [2]
  1. Vanderbilt Univ., Nashville, TN (United States). Dept. of Physics and Astronomy
  2. Stony Brook Univ., NY (United States). Dept. of Physics and Astronomy
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Univ. of California, Oakland, CA (United States); State Univ. of New York (SUNY), Albany, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1543531
DOE Contract Number:  
AC02-05CH11231; FG02-08ER46550
Resource Type:
Journal Article
Journal Name:
Computational Materials Science
Additional Journal Information:
Journal Volume: 154; Journal Issue: C; Journal ID: ISSN 0927-0256
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
Materials Science

Citation Formats

Liu, Jian, and Allen, Philip B. Internal and external thermal expansions of wurtzite ZnO from first principles. United States: N. p., 2018. Web. doi:10.1016/j.commatsci.2018.07.053.
Liu, Jian, & Allen, Philip B. Internal and external thermal expansions of wurtzite ZnO from first principles. United States. doi:10.1016/j.commatsci.2018.07.053.
Liu, Jian, and Allen, Philip B. Thu . "Internal and external thermal expansions of wurtzite ZnO from first principles". United States. doi:10.1016/j.commatsci.2018.07.053.
@article{osti_1543531,
title = {Internal and external thermal expansions of wurtzite ZnO from first principles},
author = {Liu, Jian and Allen, Philip B.},
abstractNote = {Many crystals contain “internal” structural parameters not completely constrained by symmetry. These vary with temperature T, similar to the variation of “external” structural parameters that describe the unit cell. The term “thermal expansion” most often refers to the external parameters, which are more easily and accurately measured. Here we use “thermal expansion” to mean both external and internal parameters. Internal thermal expansion impacts a wide range of applications, but has been given less attention. In this study, the thermal expansion behavior of wurtzite ZnO is studied from first principles with the generalized Grüneisen theory in the framework of quasi-harmonic approximation (QHA). Negative external thermal expansions are found below the temperature of 150 K. We demonstrate that the so-called “zero static internal stress approximation” (ZSISA) gives the correct external but incorrect internal thermal expansions, due to the neglect of the clamped-lattice internal contribution contained in the generalized Grüneisen theory. Although accurate at low T, at higher T the QHA may need to be supplemented by higher order anharmonic corrections.},
doi = {10.1016/j.commatsci.2018.07.053},
journal = {Computational Materials Science},
issn = {0927-0256},
number = C,
volume = 154,
place = {United States},
year = {2018},
month = {11}
}