Temperature scales of magnetization oscillations in an asymmetric quantum dot

The temperature scales of different types of magnetization oscillations in a:quantum dot, formed in a two-dimensional electron gas by circularly symmetric or asymmetric confining potentials, are studied. Aharonov-Bohm (AB) oscillations, with a superimposed fine structure caused by magnetic-field-induced shifts of the electronic energy levels, develop at low magnetic fields omega (c) << omega (x,y) (where omega (c) is the cyclotron frequency and omega (x,y) are the harmonic confining frequencies that determine the shape and effective size of the dot). The characteristic scale of the fine-structure fluctuations is phi (0)/(epsilon (F)/(h) over bar omega (0)) (where phi (0) is the flux quantum, epsilon (F) is the Fermi energy, and omega (0) = root omega (x)omega (y)) and they are smeared at temperatures T>((h) over bar omega (o))(2)/epsilon (F), with restoration of the oo pure AB picture for T less than or equal to(h) over bar omega (0). At high magnetic fields, omega (c)>>omega (x,y) de Haas-van Alphen oscillations develop (for T less than or equal to(h) over bar omega (c)), with a superimposed AB oscillatory structure which undergoes temperature smearing for T greater than or equal to(h) over bar omega (0)(omega (0)/omega (c)). Effects of the asymmetry of the confining potential on the magnetization oscillations are discussed. The magnetic moment of the dot as a function of the chemical potential exhibits a series of paramagnetic peaks superimposed on a diamagnetic background, and the influence of the magnetic-field strength and asymmetry of the dot on these features is discussed.