THE POSSIBILITY OF OPTICAL-DETECTION OF GENERALIZED WIGNER-CRYSTAL STATES IN RESTRICTED-DIMENSIONAL NANOSTRUCTURES

We discuss the possible detection of the onset of Wigner crystallization in 2-D electron systems (2-DES) using light scattering techniques. It is proposed that the transverse-like hybrid magneto-phonon mode with k 3 2 could be detected by light scattering owing to the unusually short Brillouin-zone wavevector of the Wigner lattice. The effect can be enhanced by the use of a specially prepared nanostructure where the 2-D layers are arranged in a superlattice along the z-direction, while each 2-D layer (x-y plane) is gated to be in the form of 2-D electron strips alternating with electron-free regions. The effect of the superlattice in the z-direction is to stabilize the Wigner crystal, while the effect of the in-plane periodic gating is to create folded transverse phonon modes of the Wigner lattice. Folding helps to access higher k-values in the dispersion. We consider the nature of the Wigner lattice of the 2-D electrons confined in strips, placed in a suitable magnetic field. It is found that these restricted geometries support a wide variety of Wigner lattices besides the usual hexagonal lattice of the infinite 2-D system. Here we consider the "toy model" of a quasi-one dimensional strip and discuss the stable lattices as a function of the filling factor. The ground state configurations of these restricted 2-DES are closely related to those of t-J type model Hamiltonians studied recently in relation to high temperature superconductors and anyon excitations. © 1992.