Wigner molecules in phosphorene quantum dots

We study Wigner crystallization of electron systems in phosphorene quantum dots with confinement an electrostatic origin both circular and elongated geometry. The anisotropy the effective mass allows for formation molecules laboratory frame a confined charge density that has lower symmetry than potential. find separate single-electron islands are formed two four electrons but not three trapped carriers. spectral signatures to be resolved by transport spectroscopy discussed. Systems molecule states characterized nearly degenerate ground state at $B=0$ easily spin-polarized external magnetic field. In which formed, more even distribution excited is observed, system undergoes transitions fields order 1 Tesla. five dot indicated as special case configurations appear ground-state field changed: one single other where only pair-correlation function inner coordinates molecular form electrons. quasi-1D easier orientation along zigzag direction heavier mass. smaller armchair freezing out transverse degree freedom motion.