Magnetic susceptibilities in mesoscopic cylinders

We calculate and discuss orbital magnetic susceptibilities in mesoscopic cylinders made of a normal metal or a semiconductor for different shapes of the Fermi surfaces and for different circumferences of the cylinders

Electromagnetic properties of mesoscopic cylinder

The electromagnetic response of a mesoscopic cylinder made of a normal metal or a semiconductor is studied. The relation between the induced current J(q, w) and the electric field E(q, w) is derived. It is shown that the kernel K(q, w) which determines the properties of the system has a finite limit which implies infinite conductivity. The mesoscopic cylinder by virtue of its topology and small dimensions can support a persistent current. If the coherence of currents from different channels is strong enough a novel effect — the self-sustaining current can be obtained. We show tlat a mesoscopic multichannel system exhibits some features which bear resemblance to the superconductor

Mutual inductance and selfinductance in mesoscopic systems

Th e role played by the magnetostatic interaction in mesoscopic multichannel systems is discussed . We show that the interaction of currents from different channels , when taken in the selfconsistent mean field approximation, leads to selfinductan ce terms in the Hamiltoni an pro ducing an internal magnetic flux. Such multichannel systems can exhibit spontaneous flux or flux expulsion. The dependence of these phenomena on the parameters of the system is discussed

Collective phenomena in multiwall carbon nanotubes

Collective phenomena due to persistent currents in carbon multiwall nanotubes are studied. The formula for persistent currents minimising free energy and conditions for the stability of persistent currents in multiwall nanotubes in magnetic field are derived. Numerical calculations performer show the possibility of obtaining spontaneous currents in two optimal configurations: undoped armchair-only multiwall nanotubes up to 0.01 K, and zig-zag{chiral¡chiral{zig-zag multiwall nanotubes doped to {3.033 eV up to about 1 K. The latter configuration may exhibit also the diamagnetic expulsion of magnetic field, which according to our calculations can reach 20% of the external °ux

Heat currents in non-superconducting flux qubits

A flux qubit based on a non-superconducting mesoscopic ring coupled to two split heat baths at different temperatures is studied. Heat currents flowing in such a nonequilibrium quantum thermodynamic system are analyzed. A method of control of heat transfer via the qubit is proposed

Effect of alloying on magnetism and electronic structure of Gd(In1-xSnx)3 system - Ab initio study

We present the results of ab initio study of electronic and magnetic properties of Gd(In1xSnx)3 alloys carried out with the use of FP-LAPW method. Our precise ab initio calculations for the rst time uniquelly con rmed experimentally based predictions that the ground state magnetic structure of the alloys is antiferromagnetic and that upon the In/Sn substitution the magnetic structure undergo transition, changing the antiferromagnetic ordering from the ( 00)-type for the GdSn3 compound to the ( 0)-type for the GdIn3 one. Moreover, calculations gave an explanation of the oscillatory variation of density of states at Fermi level indicated by XPS measurements

Wave function engineering in quantum dot-ring nanostructures

Modern nanotechnology allows producing, depending on application, various quantum nanostructures with the desired properties. These properties are strongly influenced by the confinement potential which can be modified, e.g., by electrical gating. In this paper we analyze a nanostructure composed of a quantum dot surrounded by a quantum ring. We show that depending on the details of the confining potential the electron wave functions can be located in different parts of the structure. Since the properties of such a nanostructure strongly depend on the distribution of the wave functions, varying the applied gate voltage one can easily control them. In particular, we illustrate the high controllability of the nanostructure by demonstrating how its coherent, optical, and conducting properties can be drastically changed by a small modification of the confining potential.Comment: 8 pages, 10 figures, 2 tables, revte

On the possibility of spontaneous currents in mesoscopie systems

It is shown that a mesoscopic metallic system can exhibit a phase transition to a low temperature state with a spontaneous orbital current if it is sufficiently free of elastic defect scattering. The interaction among the electrons, which is the reason of the phase transition, is of the magnetic origin and it leads to an ordered state of the orbital magnetic moments

Noise-assisted currents in a cylinder-like set of mesoscopic rings

We study magnetic fluxes and currents in a set of mesoscopic rings which form a cylinder. We investigate the noiseless system as well as the influence of equilibrium and non-equilibrium fluctuations on the properties of selfsustaining currents. Thermal equilibrium Nyquist noise does not destroy selfsustaining currents up to temperatures of the same order as the critical temperature for selfsustaining currents. For temperatures below the critical temperature, randomness in the distribution of parity of the coherent electrons can lead to disappearing of selfsustaining currents and inducing new metastable states. For temperatures above the critical temperature, it causes a creation of new metastable states with non-zero currents[…