Elastic stiffness constants of copper indium diselenide determined by neutron scattering

1993; American Physical Society; Volume: 47; Issue: 13 Linguagem: Inglês

10.1103/physrevb.47.8269

ISSN

1095-3795

Autores

R. Fouret, B. Hennion, J. González, S. M. Wasim,

Tópico(s)

Advanced Thermoelectric Materials and Devices

Resumo

From the acoustic-dispersion curves determined by inelastic neutron scattering, we obtain at room temperature the elastic stiffness constants of ${\mathrm{CuInSe}}_{2}$: at ${10}^{10}$ ${\mathrm{Nm}}^{\mathrm{\ensuremath{-}}1}$, ${\mathit{c}}_{11}$=9.70, ${\mathit{c}}_{12}$=5.97, ${\mathit{c}}_{13}$=8.60, ${\mathit{c}}_{33}$=10.89, and ${\mathit{c}}_{44}$=3.62. A theoretical calculation based upon the sphalerite approximation gives good agreement with the values of ${\mathit{c}}_{11}$ and ${\mathit{c}}_{44}$. Using the elastic constants, the isothermal compressibility is calculated along the c axis and the ab plane. Two low-energy optical modes were also observed at frequencies near 55 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ at the Brillouin-zone center.

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