Stability Region of the Two‐Dimensional Electron Crystal in Strong Magnetic Fields

In the self‐consistent harmonic approximation equations are obtained for the frequency spectrum of a two‐dimensional electron crystal in a magnetic field H . From the condition of the existence of “soft” mode peculiar for the crystal at H ≠ 0 the absolute stability curve of the crystal is analyzed. The stability region increases with H . In the H ‐n phase diagram at temperature T = 0 (n is the electron density) along the stability curve obtained the phenomenological Lindemann‐type rule 〈 u 2 〉/ b 2 γ = const. is fulfilled for strong H with γ ≈ 0.06 (〈 u 2 〉 is the mean square amplitude in the harmonic approximation, b is the lattice period). At H → 0 the Lindemann‐type constant γ decreases. The phase diagram of the two‐dimensional electron system and effects of H on the electronic crystal‐isotropic liquid and liquid‐electronic crystal‐isotropic liquid transitions are discussed.