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Isotopic dependence of the heat capacity of c-C, Si, and Ge: an ab initio calculation
被引:33
|作者:
Sanati, M
Estreicher, SK
Cardona, M
机构:
[1] Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany
[2] Texas Tech Univ, Dept Phys, Lubbock, TX 79409 USA
关键词:
diamond;
germanium;
silicon;
heat capacity;
stable isotopes;
D O I:
10.1016/j.ssc.2004.04.043
中图分类号:
O469 [凝聚态物理学];
学科分类号:
070205 ;
摘要:
The vibrational spectra of crystalline diamond, silicon, and germanium are calculated with a first-principles local density functional scheme using 64 as well as 128 atoms supercells. The (harmonic) dynamical matrices are obtained from linear response theory. The phonon density of states, calculated for various isotopic masses M, are used to evaluate the vibrational heat capacities C-v and their dependence on M at low temperatures. Simple rules obeyed by the isotope effect of C-v are discussed. The results are compared with recent experimental data for Ge. It is hoped that this work will encourage and help to interpret analogous measurements in diamond and silicon with different isotopic compositions. (C) 2004 Elsevier Ltd. All rights reserved.
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页码:229 / 233
页数:5
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