We report investigations at microwave frequencies on surface-state electrons (SSE) which were supported by helium films adsorbed on different polymer substrates at temperatures above 1 K. The real and imaginary parts of the dielectric response epsilon(k,omega) of the SSE were measured at fixed k and omega inside a 10 GHz microwave cavity. The solidification of the two-dimensional electron crystal was detected by a kink occurring simultaneously in both components of epsilon(k,omega) as the electron density was slowly increased at constant temperature. The influence of the dielectric substrate on such a freezing transition has been measured at different temperatures and at various helium-film thicknesses. The results are found to be in good agreement with existing theories. This work represents the first systematic study of a screened two-dimensional electron crystal on helium.
Microwave study of screened two-dimensional electron crystals on helium films
MISTURA, GIAMPAOLO;
1997
Abstract
We report investigations at microwave frequencies on surface-state electrons (SSE) which were supported by helium films adsorbed on different polymer substrates at temperatures above 1 K. The real and imaginary parts of the dielectric response epsilon(k,omega) of the SSE were measured at fixed k and omega inside a 10 GHz microwave cavity. The solidification of the two-dimensional electron crystal was detected by a kink occurring simultaneously in both components of epsilon(k,omega) as the electron density was slowly increased at constant temperature. The influence of the dielectric substrate on such a freezing transition has been measured at different temperatures and at various helium-film thicknesses. The results are found to be in good agreement with existing theories. This work represents the first systematic study of a screened two-dimensional electron crystal on helium.Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.