Optical absorption spectra of GaSe samples immersed in superfluid helium have been measured as a function of the optical excitation intensity, by using a two beam technique. As the electron-hole density increases a broadening and a red-shift of the fundamental excitonic absorption line occur. We compare our observation with the results of a simplified first order theory which accounts for electron-hole correlation effects in state screening approximation. The optical spectra, both calculated theoretically and observed experimentally, suggest that the observed Mott transition is, at finite temperatures, smooth and continuous. Our simple model explains the observed spectra.
Red-shift of the Excitonic Level in Two Beam Absorption Spectra of GaSe
CAPOZZI, VITO GIACOMO;
1988-01-01
Abstract
Optical absorption spectra of GaSe samples immersed in superfluid helium have been measured as a function of the optical excitation intensity, by using a two beam technique. As the electron-hole density increases a broadening and a red-shift of the fundamental excitonic absorption line occur. We compare our observation with the results of a simplified first order theory which accounts for electron-hole correlation effects in state screening approximation. The optical spectra, both calculated theoretically and observed experimentally, suggest that the observed Mott transition is, at finite temperatures, smooth and continuous. Our simple model explains the observed spectra.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
