CURRENT MAGNIFICATION AND CIRCULATING CURRENTS IN MESOSCOPIC RINGS

TL;DR

This paper investigates novel persistent current phenomena in open mesoscopic rings, revealing effects like current magnification and sensitivity to current direction, influenced by magnetic fields and quantum effects, distinct from closed systems.

Contribution

It introduces the concept of persistent currents in open systems with transport currents, highlighting effects absent in isolated systems, such as current magnification and directional sensitivity.

Findings

Persistent currents can flow without magnetic field due to current magnification.

Amplitude of persistent currents depends on current flow direction in magnetic fields.

Quantum effects like Aharonov-Bohm and tunneling influence persistent currents.

Abstract

We show that several novel effects related to persistent currents can arise in open systems, which have no analogue in closed or isolated systems. We have considered a system of a metallic ring coupled to two electron reservoirs. We show that in the presence of a transport current, persistent currents can flow in a ring even in the absence of magnetic field. This is related to the current magnification effect in the ring. In the presence of magnetic field we show that the amplitude of persistent currents is sensitive to the direction of current flow from one reservoir to another. Finally we briefly discuss the persistent currents arising due to two nonclassical effects namely, Aharonov-Bohm effect and quantum tunneling.