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 ${\ensuremath{\omega}}_{c}\ensuremath{\ll}{\ensuremath{\omega}}_{x,y}$ (where ${\ensuremath{\omega}}_{c}$ is the cyclotron frequency and ${\ensuremath{\omega}}_{x,y}$ are the harmonic confining frequencies that determine the shape and effective size of the dot). The characteristic scale of the fine-structure fluctuations is ${\ensuremath{\varphi}}_{0}/({\ensuremath{\varepsilon}}_{F}/\ensuremath{\Elzxh}{\ensuremath{\omega}}_{0})$ (where ${\ensuremath{\varphi}}_{0}$ is the flux quantum, ${\ensuremath{\varepsilon}}_{F}$ is the Fermi energy, and ${\ensuremath{\omega}}_{0}=\sqrt{{\ensuremath{\omega}}_{x}{\ensuremath{\omega}}_{y}})$ and they are smeared at temperatures $Tg(\ensuremath{\Elzxh}{\ensuremath{\omega}}_{0}{)}^{2}/{\ensuremath{\varepsilon}}_{F},$ with restoration of the pure AB picture for $Tl~\ensuremath{\Elzxh}{\ensuremath{\omega}}_{0}.$ At high magnetic fields, ${\ensuremath{\omega}}_{c}\ensuremath{\gg}{\ensuremath{\omega}}_{x,y},$ de Haas\char21{}van Alphen oscillations develop (for $Tl~\ensuremath{\Elzxh}{\ensuremath{\omega}}_{c}),$ with a superimposed AB oscillatory structure which undergoes temperature smearing for $Tg~\ensuremath{\Elzxh}{\ensuremath{\omega}}_{0}({\ensuremath{\omega}}_{0}/{\ensuremath{\omega}}_{c}).$ 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.