Why are large persistent currents observed in small gold rings?

Semiconductor Analog of the Large Persistent Currents Observed in Small Gold Rings

Persistent spin currents in mesoscopic Heisenberg rings.

We show that at low temperatures T an inhomogeneous radial magnetic field with magnitude B gives rise to a persistent magnetization current around a mesoscopic ferromagnetic Heisenberg ring. Under optimal conditions, this spin current can be as large as gmicro(B)(T/ variant Planck's over 2pi )exp([-2pi(gmicro(B)B/delta)(1/2)], as obtained from leading-order spin-wave theory. Here g is the gyrom...

Persistent currents in carbon nanotubes based rings

Persistent currents in rings constructed from carbon nanotubes are investigated theoretically. After studying the contribution of finite temperature or quenched disorder on covalent rings, the complexity due to the bundle packing is addressed. The case of interacting nanotori and self-interacting coiled nanotubes are analyzed in details in relation with experiments.

Persistent currents in carbon nanotube based rings

Carbon nanotubes are micrometer-long hollow cylinders with nanometer scale radii, and electronic properties strongly depending on their geometrical helicity. As promising tools for building up nanoscale electronic devices, nanotubes also allow one to challenge the well established common theories of mesoscopic physics. Recently, many works of quantum transport in these systems have revealed puz...

Persistent currents in normal metal rings.

The authors have measured the magnetic response of 33 individual cold mesoscopic gold rings, one ring at a time. The response of some sufficiently small rings has a component that is periodic in the flux through the ring and is attributed to a persistent current. Its period is close to h/e, and its sign and amplitude vary between rings. The amplitude distribution agrees well with predictions fo...