ENERGY-SPECTRA AND QUANTUM CRYSTALLIZATION IN 2-ELECTRON QUANTUM DOTSIN A MAGNETIC-FIELD

Quantum crystallization of electrons in a quantum dot (QD) subjected t o an external magnetic field is considered. Two-electron QDs with two- dimensional (2D) parabolic confining potential in an external transver se magnetic field are calculated. The Hamiltonian is numerically diago nalized in the basis of one-particle functions to find the energy spec tra and wave functions for the relative motion of electrons with inclu sion of electron-electron interaction for a broad range of the confini ng-potential steepness (alpha) and external magnetic fields (B). The r egion of the external parameters (alpha, B) within which a gradual tra nsition to quantum crystalline order occurs is numerically determined. In contrast to a 2D unbounded system, a magnetic field acts nonmonoto nically on ''crystallization'' in a quantum dot with several electrons because of a competition between two effects taking place with increa sing B, namely, decreasing spread of the electron wave functions and i ncreasing effective steepness of the confining potential, which reduce s the average separation between electrons. (C) 1998 American Institut e of Physics. [S1063-7834(98)03909-4].