Magnetic Response in Mesoscopic Hubbard Rings: A Mean Field Study

The present work proposes an idea to remove the long standing controversy between the calculated and measured current amplitudes carried by a small conducting ring upon the application of an Aharonov-Bohm (AB) flux $\phi$. Within a mean field Hartree-Fock (HF) approximation we numerically calculate persistent current, Drude weight, low-field magnetic susceptibility and related issues. Our analysis may be inspiring for studying magnetic response in nano-scale loop geometries.Comment: 8 pages, 8 figure

Magneto-transport in mesoscopic rings and cylinders: Effects of electron-electron interaction and spin-orbit coupling

We undertake an in-depth analysis of the magneto-transport properties in mesoscopic single-channel rings and multi-channel cylinders within a tight-binding formalism. The main focus of this review is to illustrate how the long standing anomalies between the calculated and measured current amplitudes carried by a small conducting ring upon the application of a magnetic flux $\phi$ can be removed. We discuss two different cases. First, we examine the combined effect of second-neighbor hopping integral and Hubbard correlation on the enhancement of persistent current in presence of disorder. A significant change in current amplitude is observed compared to the traditional nearest-neighbor hopping model and the current amplitude becomes quite comparable to experimental realizations. In the other case we verify that in presence of spin-orbit interaction a considerable enhancement of persistent current amplitude takes place, and the current amplitude in a disordered ring becomes almost comparable to that of an ordered one. In addition to these, we also present the detailed band structures and some other related issues to get a complete picture of the phenomena at the microscopic level.Comment: 17 pages, 22 figures (An invited review article

Implementation of Nano-scale Rectifiers: An Exact Study

We propose the possibilities of designing nano-scale rectifiers using mesoscopic rings. A single mesoscopic ring is used for half-wave rectification, while full-wave rectification is achieved using two such rings and in both cases each ring is threaded by a time varying magnetic flux $\phi$ which plays a central role in the rectification action. Within a tight-binding framework, all the calculations are done based on the Green's function formalism. We present numerical results for the two-terminal conductance and current which support the general features of half-wave and full-wave rectifications. The analysis may be helpful in fabricating mesoscopic or nano-scale rectifiers.Comment: 5 pages, 6 figure