Polarized far-infrared and Raman spectra of SrCuO2 single crystals

Дата и время публикации : 2000-10-16T16:12:12Z

Авторы публикации и институты :
Z. V. Popović (VSM-Lab, K. U. Leuven, Belgium, Institute of Physics – Belgrade, Yugoslavia)
M. J. Konstantinović (MPI-FKF, Stuttgart, F. R. Germany, Institute of Physics – Belgrade, Yugoslavia)
R. Gajić (Institute of Physics – Belgrade, Yugoslavia)
C. Thomsen (Institut für Festkörperphysik, TU-Berlin, Germany)
U. Kuhlmann (Institut für Festkörperphysik, TU-Berlin, Germany)
A. Vietkin (Physics Department, MSU-Moscow, Russia)

Ссылка на журнал-издание: Physica C 351, 386 (2001)
Коментарии к cтатье: to be published in Physica C
Первичная категория: cond-mat.str-el

Все категории : cond-mat.str-el

Краткий обзор статьи: We measured polarized far-infrared reflectivity and Raman scattering spectra of SrCuO$_2$ single crystals. The frequencies for infrared-active modes were determined using an oscillator-fitting procedure of reflectivity data. The Raman spectra were measured at different temperatures using several laser energies $omega_L$. In addition to eight of twelve Raman active modes, predicted by factor-group analysis, we observed a complex structure in the Raman spectra for polarization parallel to the {bf c}-axis, which consists of Raman-allowed A$_g$ symmetry modes, and B$_{1u}$ LO infrared-active (Raman-forbidden) modes of the first and higher order as well as their combinations. The Raman-forbidden modes have a stronger intensity at higher $omega_L$ than the Raman-allowed ones. In order to explain this resonance effect, we measured the dielectric function and optical reflection spectra of SrCuO$_2$ in the visible range. We show that the Raman-allowed A$_g$ symmetry modes are resonantly enhanced when a laser energy is close to $E_0$, while Raman-forbidden (IR-active) modes resonate strongly for laser line energies close to the electronic transition of higher energy gaps.

Category: Physics