Temperature dependent diamagnetic-paramagnetic transitions in metal/semiconductor quantum rings

Abstract

We present theoretical studies of temperature dependent diamagnetic-paramagnetic transitions in thin quantum rings. Our studies show that the magnetic susceptibility of metal/semiconductor rings can exhibit multiple sign flips at intermediate and high temperatures depending on the number of conduction electrons in the ring ($N$) and whether or not spin effects are included. When the temperature is increased from absolute zero, the susceptibility begins to flip sign above a characteristic temperature that scales inversely with the number of electrons according to $N^{-1}$ or $N^{-1/2}$, depending on the presence of spin effects and the value of $N\mathrm{mod}4$. Analytical results are derived for the susceptibility in the low and high temperature limits, explicitly showing the spin effects on the ring Curie constant.

References in corpus (16)

• Spectroscopy of nanoscopic semiconductor rings
• Energy spectra of quantum rings
• Quantum rings for beginners: Energy spectra and persistent currents
• Persistent currents in normal metal rings
• Diamagnetic orbital response of mesoscopic silver rings
• Spin-like susceptibility of metallic and insulating thin films at low temperature
• Effect of pair-breaking on mesoscopic persistent currents well above the superconducting transition temperature
• Persistant Current in Isolated Mesoscopic Rings
• Tunable negative permeability in a quantum plasmonic metamaterial
• Persistent currents in one dimension: the other side of Leggett's theorem
• Bounds on quantum confinement effects in metal nanoparticles
• Orbital magnetism in ensembles of gold nanoparticles
• Relativistic fermion on a ring: Energy spectrum and persistent current
• Current-flux characteristics in mesoscopic nonsuperconducting rings
• Diamagnetism of metallic nanoparticles as the result of strong spin-orbit interaction
• Equilibrium properties of mesoscopic quantum conductors