Related papers: Parity Effect in a mesoscopic superconducting ring
Starting from the Ginzburg-Landau energy functional, we discuss how the presence of two order parameters and the coupling between them influence a superconducting ring in the fluctuative regime. Our method is exact, but requires numerical…
We study the superconductivity in small grains in the regime when the quantum level spacing $\delta\varepsilon$ is comparable to the gap $\Delta$. As $\delta\varepsilon$ is increased, the system crosses over from superconducting to normal…
Recently, it has been possible to construct single-electron transistors to study electronic properties, including superconductivity, in metallic grains of nanometer size. Among several theoretical results are suppression of…
The observations the dc voltage on asymmetric superconducting ring testify that one of the ring segments is a dc power source. The persistent current flows against the total electric field in this segment. This paradoxical phenomenon is…
Recent experiments on the proximity induced supercurrent in mesoscopic normal wires revealed a surprising temperature dependence. They suggest clean-limit behavior although the wires are strongly disordered. We demonstrate that this…
A microscopic model is constructed which is able to describe multiple magnetic flux transitions as observed in recent ultra-low temperature tunnel experiments on an aluminum superconducting ring with normal metal - insulator -…
The electronic transport in a system of two quantum rings side-coupled to a quantum wire is studied via a single-band tunneling tight-binding Hamiltonian. We derived analytical expressions for the conductance, density of states and the…
The parity effect in an ultra-small superconducting grain is examined. By applying a generalized version of Lieb's spin-reflection positivity technique, we show rigorously that the parity parameter $\Delta_P$ is nonvanishing in such a…
Generalized BCS equations which consistently include the projection on the particle-number parity are derived from a systematic variational method. Numerical solutions are given that are illustrative of ultra-small metallic grains. Compared…
Superfluidity and superconductivity are genuine many-body manifestations of quantum coherence. For finite-size systems the associated pairing gap fluctuates as a function of size or shape. We provide a parameter free theoretical description…
We show that a magnetic field can influnce the proximity effect in NS junctions via diamagnetic screening current flowing in the superconductor. Using ballistic quasi-one-dimensional (Q1D) electron channels as an example, we show that the…
In normal mesoscopic metals of a ring topology persistent currents can be induced by threading the center of the ring with a magnetic flux. This phenomenon is an example of the famous Aharonov-Bohm effect. In the paper we study the current…
We consider a mesoscopic normal metal, where the spin degeneracy is lifted by a ferromagnetic exchange field or Zeeman splitting, coupled to two superconducting reservoirs. As a function of the exchange field or the distance between the…
The helical edge state of a quantum spin-Hall insulator can carry a supercurrent in equilibrium between two superconducting electrodes (separation L, coherence length xi). We calculate the maximum (critical) current I_c that can flow…
We investigate a mesoscopic spin current for strongly interacting Fermi gases through a quantum point contact. Under the situation where spin polarizations in left and right reservoirs are same in magnitude but opposite in sign, we…
The thermopower of mesoscopic normal metal/superconductor structures has been measured at low temperatures. Effect of supercurrent present in normal part of the structure was studied in two cases: when it was created by applied external…
It has been shown[19] that in a loop of length u to which a single stub of length v is attached (fig. 1 in ref. 19), the parity effect is completely destroyed when v/u$>2$. It was also shown that such minute topological defects (v/u$<<1$)…
The superconducting pairing instability---as determined by a divergence of the two-particle susceptibility---is obtained in the mean field (BCS) approximation in the thermodynamic limit. The usual practice is to examine this property for a…
In the framework of the Ginzburg-Landau equation, the temperature dependence of the upper critical field of small ring-like superconductors is studied. At equilibrium small parts of the phase diagram show paramagnetism for width / radius…
Spin states and persistent currents are investigated theoretically in a mesoscopic ring with an embedded magnetic ion under a uniform magnetic field including the spin-orbit interactions. The magnetic impurity acts as a spin-dependent…