Magnetoshear modes and ac dissipation in a two-dimensional Wigner crystal

Article

关键词: LIQUID-HELIUM SURFACE;    MAGNETIC-FIELD;    SUPERFLUID-HELIUM;    SHEAR MODES;    MAGNETOCONDUCTIVITY;    ELECTRONS;    IONS;    TRANSITION;    PHASE;   

DOI  :  10.1103/PhysRevB.58.13197

来源: SCIE

【 摘 要 】

The ac response of an unpinned and finite two-dimensional (2D) Wigner crystal to electric fields at an angular frequency omega has been calculated in the dissipative limit, omega tau much less than 1, where tau(-1) is the scattering rate. For electrons screened by parallel electrodes, in zero magnetic field the long-wavelength excitations are a diffusive longitudinal transmission line mode and a diffusive shear mode. A magnetic field couples these modes together to form two new magnetoshear modes. The dimensionless coupling parameter beta = 2(c(t)/c(l))/sigma(xy) /sigma(xx)/, where c(t) and c(l) are the speeds of transverse and longitudinal sound in the collisionless limit, and sigma(xy) and sigma(xx) are the tensor components of the magnetoconductivity. For beta greater than or similar to 1, both the coupled modes contribute to the response of 2D electrons in a Corbino disk measurement of magnetoconductivity. For beta much greater than 1, the electron crystal rotates rigidly in a magnetic field. In general, both the amplitude and phase of the measured ac currents are changed by the shear modulus. In principle, both the magnetoconductivity and the shear modulus can be measured simultaneously. [S0163-1829(98)04440-3].

【 授权许可】

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