Influence of temperature on magnetism in a quantum confined system

In this article, we present new formulas to describe the relation between t emperature and average spin in a quantum confined system by using a Green's function approach. We focus on a lattice of quantum dots, each of which co nfines several electrons on the sites of the confined crystal lattice under the influence of an external magnetic field. Our treatment makes use of th e Heisenberg model, subject to a transverse magnetic field. We show that at low temperatures, the temperature dependence of magnetic moment differs fr om a 3/2 power law, and present a unique signature for temperatures approac hing or beyond the phase transition temperature. (C) 2000 American Institut e of Physics. [S0021-8979(00)00805-7].