Exciton Condensation and Superfluidity in TmSe_0.45Te_0.55  

作　　者：P. Wachter 

机构地区：[1]Laboratorium für Festkö rperphysik, ETH Zürich, Zürich, Switzerland

出　　处：《Advances in Materials Physics and Chemistry》2018年第3期120-142,共23页材料物理与化学进展（英文）

摘　　要：In this publication details of the calculation of heat conductivity and thermal diffusivity, compressibility, sound velocity and exciton-polaron dispersion of TmSe0.45Te0.55 will be shown. The properties of excitons, coupling to phonons, producing thus polarons, but also blocking the phonons as running waves lead to an exciton condensation or exciton liquid. Surprisingly this exciton liquid is contained in a macroscopic crystal, a solid nevertheless, which becomes extremely hard due to the exciton liquid and finally exhibits a strange type of superfluid in a two fluid model, where the superfluid phase increases more and more below about 20 K until the whole exciton liquid becomes a superfluid at zero temperature. Never else a superfluid phase has been observed at such high temperatures.In this publication details of the calculation of heat conductivity and thermal diffusivity, compressibility, sound velocity and exciton-polaron dispersion of TmSe0.45Te0.55 will be shown. The properties of excitons, coupling to phonons, producing thus polarons, but also blocking the phonons as running waves lead to an exciton condensation or exciton liquid. Surprisingly this exciton liquid is contained in a macroscopic crystal, a solid nevertheless, which becomes extremely hard due to the exciton liquid and finally exhibits a strange type of superfluid in a two fluid model, where the superfluid phase increases more and more below about 20 K until the whole exciton liquid becomes a superfluid at zero temperature. Never else a superfluid phase has been observed at such high temperatures.

关 键 词：Exciton-Polarons SUPERFLUIDITY EXCITON CONDENSATION Heat Conductivity Compressibility Sound Velocity 

分 类 号：O4[理学—物理]