Temperature enhanced persistent currents and "${\varphi }_0/2$ periodicity"

Abstract

We predict a non-monotonous temperature dependence of the persistent currents in a ballistic ring coupled strongly to a stub in the grand canonical as well as in the canonical case. We also show that such a non-monotonous temperature dependence can naturally lead to a ${\varphi }_0/2$ periodicity of the persistent currents, where ${\varphi }_0$=h/e. There is a crossover temperature $T^{\ast }$, below which persistent currents increase in amplitude with temperature while they decrease above this temperature. This is in contrast to persistent currents in rings being monotonously affected by temperature. $T^{\ast }$ is parameter-dependent but of the order of ${\Delta }_u/{\pi }^2{k}_B$, where ${\Delta }_u$ is the level spacing of the isolated ring. For the grand-canonical case $T^{\ast }$ is half of that for the canonical case.

some typos corrected

References in corpus (2)

• Generic transmission zeros and in-phase resonances in time-reversal symmetric single channel transport
• Friedel phases and phases of transmission amplitudes in quantum scattering systems

Cited by in corpus (4)

• Renormalization group study of the conductances of interacting quantum wire systems with different geometries
• Temperature-dependent periodicity of the persistent current in strongly interacting systems
• Charge and spin polarized currents in mesoscopic rings with Rashba spin-orbit interactions coupled to an electron reservoir
• Exact and mean-field analysis of the role of Hubbard interactions on flux driven circular current in a quantum ring