6 research outputs found
Magneto-shear modes and a.c. dissipation in a two-dimensional Wigner crystal
The a.c. response of an unpinned and finite 2D Wigner crystal to electric
fields at an angular frequency has been calculated in the dissipative
limit, , where 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 magneto-shear modes. The dimensionless coupling parameter where and are the
speeds of transverse and longitudinal sound in the collisionless limit and
and are the tensor components of the
magnetoconductivity. For , both the coupled modes contribute
to the response of 2D electrons in a Corbino disk measurement of
magnetoconductivity. For , the electron crystal rotates rigidly in
a magnetic field. In general, both the amplitude and phase of the measured a.c.
currents are changed by the shear modulus. In principle, both the
magnetoconductivity and the shear modulus can be measured simultaneously.Comment: REVTeX, 7 pp., 4 eps figure