The ground state of a two-dimensional electron system in a strong magnetic field is investigated under the condition that only the ground Landau level is partially filled. Within the unrestricted Hartree-Fock approximation the ground state proves to be a charge-density-wave (CDW) state. When the density is low, wave functions of nearby lattice sites are well separated so that the CDW is regarded as a classical Wigner crystal. It is shown that the amplitude of the CDW is very large at arbitrary densities. Density dependence of the ground state energy is discussed using (1) a unidirectional CDW structure which allows one to take full account of the exchange effect, and (2) the square lattice for which self-consistent solution is obtained in the case of the half-filled Landau level as well as in the low density classical regime.
ASJC Scopus subject areas
- Physics and Astronomy(all)