Figure 1
From: Phonon anharmonicities and ultrafast dynamics in epitaxial Sb2Te3
(a) Temperature dependent THz transmittance change of Sb2Te3. Curves are normalized to the empty case with a baseline becoming more noisy at around 300 K. (b) Eu phonon mode softening upon temperature decrease. (c) Experimental change (squares) of the peak width (FWHM) and fit (red line) as described in the text. (d) Raman spectra of the same Sb2Te3 sample measured at 300 K and 10 K with labeled modes1,6. Hardening of all modes is observed as T is decreased, as opposed to the IR active mode in (b). (e) Electrical measurement of free carrier increase upon temperature change. The error on the carrier measurement is < 4%. Color code corresponding to the different temperatures is reported in the legend in (a). Colored graded arrows indicate mode softening for the IR-active mode and mode hardening for all Raman modes upon temperature decrease, respectively.
