Jh. Davies et al., THEORY OF POTENTIAL MODULATION IN LATERAL SURFACE SUPERLATTICES - III- 2-DIMENSIONAL SUPERLATTICES AND ARBITRARY SURFACES, Physical review. B, Condensed matter, 58(16), 1998, pp. 10789-10799
We have calculated the potential energy induced in a two-dimensional e
lectron gas by a two-dimensional array of gates on the surface of a he
terostructure. Differential thermal contraction of the gates generates
strain that couples to the electrons by the deformation potential and
piezoelectric effect. The piezoelectric effect usually dominates, and
its angular dependence breaks the symmetry of the gate or array. For
example, the potential under a circular gate on a (100) surface varies
as sin 2 theta, where theta is measured from the [010] axis. This nul
ls the lowest Fourier components of the potential from a square array
of gates aligned parallel to the principal axes. The lowest surviving
component has a smaller period than the gates, and is rotated with res
pect to them by 45 degrees. Arrays are usually aligned parallel to the
{011} cleavage planes in practice, which causes a stronger potential
without such cancellation. We also provide results for (110), (111), a
nd (311) surfaces; (111) may be attractive because the piezoelectric e
ffect is nearly isotropic. The potential due to a bias on the gates, a
nd the limit of a one-dimensional array, are considered briefly. Our c
alculations are for the strain induced by metal gates but also apply t
o devices with stressors such as mismatched semiconductors. [S0163-182
9(98)06240-7].