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В. А. Николаенко, А. В. Смородин, С. С. Соколов
«Автолокализация поверхностных электронов над структурированной подложкой, покрытой гелием »
001–018 (2014)

PACS numbers: 67.25.bh, 67.25.dp, 67.80.-s, 73.20.-r, 73.25.+i, 73.90.+f

The conductivity of surface electrons over liquid-helium film covering the structured silicon substrate containing a regular system of micropores is investigated experimentally within the temperature range T???1.5–2.7 K. As found, the conductivity decreases sharply at T???2.5 K that can be explained by the formation of autolocalized polaron state of electron over the helium film. To check the hypothesis on the formation of the polaron state of surface electron in dense helium vapour, a theoretical calculation of free energy of the polaron is performed. As shown, the free energy minimum occurs when the temperature rises to a critical value corresponding to the formation of polaron and close to the temperature of the sharp decrease of conductivity observed experimentally. The calculation predicts the dependence of the critical temperature on the parameters of the effective potential acting within the plane of the surface of helium and associated with a distortion of the helium surface due to the structure of the substrate, which contributes to the appearance of localized charge on the helium film. The data of this investigation are compared with previously obtained results on autolocalization of surface electrons in quasi-1D-system.