Effect of pressure on the refractive index of Ge and GaAs
1990; American Physical Society; Volume: 41; Issue: 14 Linguagem: Inglês
10.1103/physrevb.41.10104
ISSN1095-3795
AutoresA.R. Go�i, K. Syassen, M. Cardona,
Tópico(s)Advanced Chemical Physics Studies
ResumoWe have measured the dispersion of the refractive index n(\ensuremath{\omega}) of Ge and GaAs between 0.6 and 1.4 eV for hydrostatic pressures up to 8 GPa. The frequency dependence of n(\ensuremath{\omega}) is extrapolated to zero energy by using an oscillator model of the dielectric function. In this way, we obtain the variation with pressure of the electronic static dielectric constant ${\mathrm{\ensuremath{\epsilon}}}_{\mathrm{\ensuremath{\infty}}}$. We find that for the volume change of \ensuremath{\Delta}V/${\mathit{V}}_{0}$\ensuremath{\approxeq}8% covered in this experiment the volume dependence of ${\mathrm{\ensuremath{\epsilon}}}_{\mathrm{\ensuremath{\infty}}}$ is well described by a single scaling coefficient r=d ln${\mathrm{\ensuremath{\epsilon}}}_{\mathrm{\ensuremath{\infty}}}$/d lnV with r=1.58(3) for Ge and 0.73(4) for GaAs. Results are discussed in relation to semiempirical theoretical models.
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