Thermodynamic properties of an artificial molecule quantum rings: Geometric and external field effects

A systematic study of the thermal properties of an artificial molecule formed by a single electron embedded in two laterally coupled quantum rings under external probes: magnetic and static electric fields was carried out. The eigen-states and eigen-values of the Hamiltonian in the effective mass approximation were obtained numerically. By varying the distance between the centers of the rings, it was possible to establish the equilibrium length required by the formation of a giant stable artificial molecular complex and its dissociation energy. These features were corroborated by studying the effects of the distance between centers of the rings, the magnetic and electric field on the entropy and heat capacity of the system. At low temperatures, the equilibrium condition of the artificial molecule is linked to the formation of a minimum value of the entropy and a peak in the heat capacity. The temperature's rising modifies substantially these conditions.