Influence of inelastic subbarrier impurity scattering on the nonresonant tunneling transmission of a quasi-one-dimensional tunneling junction with weak structural disorder

The contribution of inelastic subbarrier impurity scattering of tunneling electrons to the nonresonant transmission of a quasi-one-dimensional tunneling junction with weak (low impurity concentrations) structural disorder at temperature T=0 is determined. It is shown that this contribution leads to an increase in the tunneling transmission and conditions are determined for which this increase may be appreciable.     

Resonance current-voltage characteristics of three-dimensional tunnel junctions with weak structural disorder

The nonlinear current-voltage characteristics of a three-dimensional tunnel junction with weak (low impurity concentration) structural disorder are obtained for temperature T=0, and a formula is derived for the magnitude of the mesoscopic fluctuations in its resonant static tunnel conductance. Zh. éksp. Teor. Fiz. 116, 1048–1057 (September 1999)     

On the current-voltage characteristic of a tunnel metal-semiconductor Schottky-Barrier contact

A possibility of a more simple and exact representation of the current-voltage (I–V) characteristic of a tunnel metal-semiconductor contact is investigated. Analysis is made on the basis of the approach proposed earlier, according to which the behaviour of the (I–V) characteristics of the Schottky-barrier contacts at low temperatures depends on the nonlinear dependence of the true (or effective for a tunnel contact) barrier height on the bias voltage. A simple equation for the (I–V) characteristic of the tunnel contact is theoretically substantiated using measurable parameters-the ideality factor n and barrier height ϕ_bm where the quantity ϕ_bn ≡ nϕ_bm plays the role of a barrier height. The calculation shows that this quantity is very close to the true barrier height of the tunnel contact (with allowance for the effect of image force) in wide current, temperature, and impurity-concentration ranges. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 18–25, March, 2006.     

Effect of normal electrons in superconductors on the current-voltage characteristic of a Josephson junction

It is established that the conductivity of normal electrons in superconductors plays a large role in the current-voltage characteristic of a Josephson junction having a high critical current density, described on the basis of a nonlocal electrodynamics. It is shown in the resistive limit that the normal-electron contribution increases the current through the Josephson junction, while in the capacitive limit it decreases the contribution of Cherenkov resonances. Fiz. Tverd. Tela (St. Petersburg) 41, 582–587 (April 1999)     

On the current-voltage characteristic of a Josephson junction with a high critical current density

A theory is constructed for the current-voltage characteristic of a Josephson junction with a high critical current density described by nonlocal vortex electrodynamics in the approximation of small dissipation due to the single-particle conductivity of the Josephson junction. The role of the resonant excitation of generalized short-wavelength Swihart waves is determined. New quantitative properties of the current-voltage characteristic, which is an envelope of wave excitation resonances, are established. Zh. éksp. Teor. Fiz. 113, 2148–2161 (June 1998)     

Influence of self-heating on the step structures in the current-voltage characteristic of superconducting films

The current-induced transition between the normal and the superconducting state of Sn, In, and Pb films is investigated by varying the helium bath temperature, film thickness, mean free path, and an external magnetic field oriented parallel to the film surface. The experiments show that, farther fromT _c , heating effects play an important role. The heating of the films relative to the helium bath by the liberation of Joule heat in the resistive state and the influence of hotspot formation on the step structures in the current-voltage characteristics of the samples are established with a graphite thermometer. the temperature and the size of the hotspots are determined by the power dissipation, the surface heat transfer, and the heat conduction within the film.     

Hysteretic effects in the dc current-voltage characteristic of normal Nb/Pb tunnel junctions

High resistance normal Nb/Pb tunnel junctions have been studied. Both at 300 K and 77 K an hysteresis in the I–V characteristic has been measured: the presence of negative or positive bias voltages changes the tunneling probability. At every fixed bias current value, a voltage drift with time appears. The drift velocity increases as the voltage or the temperature increases. Moreover at 77 K anomalous low frequency oscillations arise in the junction when some positive or negative threshold voltages are exceeded.     

Resonances in the current-voltage characteristics of a dissipative Josephson junction

The I-V characteristics of a Josephson junction shunted by an Ohmic resistor shows sharp peaks when levels in neighbouring wells are crossing. We consider the shape and size of these peaks using a double-well model where the wells are given in parabolic approximation. The friction of arbitrary strength is included by the help of a bath of infinitely many degrees of freedom. 74.50.+z.     

On the current-voltage characteristic of the oxide process

The transport equations that simulate the passage of the ionic current through an oxide layer under Steady-state conditions have been investigated. These equations are integrated by the method of matched asymptotic expansions. An analysis of the current-voltage characteristic of the system has revealed a region with negative differential conductivity. On this basis, it has been argued that the system is characterized by an instability of the initially uniform distribution of the electric current, which, in turn, leads to the appearance of “current filaments.” The threshold value of this instability is determined.     

Numerical study of the current-voltage characteristic of a plasma-filled high-current diode

A numerical study is performed of a one-dimensional model of a high current plasma-filled diode, connected in a circuit with a voltage generator. Flow of the plasma from an external source into the diode anode-cathode gap through the plane of the cathode grid proves to have a definite effect on the diode current-voltage characteristic. An estimate is made of the limiting current above which formation of a cathode double layer occurs. Generation of explosive emission at a high value of current or the time derivative of current causes rapid expansion of the cathode layer due to a lack of the majority, electron current component and the presence of a phase intensified by plasma erosion. Dependence of the current-voltage characteristic on density of cathode explosive emission centers is noted.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 48–53, October, 1988.     

Effect of tunnel resonances on fluxon radiation loss in a long S-I-S tunnel junction with weak structural disorder in the I layer

The expression for the density of the bias current, which compensates for the radiation loss of a fluxon moving in an S-I-S (superconductor-insulator-superconductor) tunnel junction with tunnel resonances-quantum resonant percolation trajectories (quantum jumpers), randomly formed in the disordered I layer [1], has been derived. The substantial physical difference between the described model and the model with microjumpers in the I layer [2] is that radiation friction acts on fluxon only in the narrow energy range of tunnel resonances.     

Estimation of the current-voltage characteristic of an open discharge

The simplest mathematical model for describing the processes in the electron beam generators based on an open discharge (i.e., high-voltage glow discharge with electron runaway) is considered. On the basis of the model, the discharge current-voltage characteristic is found. The resultant dependences are compared with experimental results.     

Empirical model for the current-voltage characteristic of resonant-tunneling devices

An empirical model is presented for the current-voltage characteristics of resonanttunneling (RT) devices. By using this model an analytical study of millimeter-band electronic circuits employing RT devices can be performed.     

Hysteresis and negative differential resistance of the current-voltage characteristic of a water bridge

It is found experimentally that the properties of nanoporous ion-exchange membranes (hysteresis of the current-voltage characteristic in the solution and negative differential resistance), which have been discussed in recent years, are not associated with the properties of the membrane. It is shown that these effects are also observed in a floating water bridge and in water-filled tubes and are apparently determined by the geometrical shape of the liquid conductor. The observed effects are explained qualitatively.     

Spin current through a tunnel junction

We derive an expression for the spin current through a tunnel barrier in terms of many-body Green’s functions. The spin current has two possible contributions. One is associated with angular momentum transfer due to spin-polarized charge current crossing the junction. If there are magnetic moments on both sides of the tunnel junction, due to spin accumulation or ferromagnetic ordering, then there is a second contribution related to the exchange coupling between the moments.     

Criterial generalization of the current-voltage characteristic of a negative corona in the argon flow

The current-voltage curves of the corona discharge are generalized using energy and gasdynamic criteria characterizing a relation between the processes taking place in the corona column and corona existence regime.     

Calculations of the current-voltage characteristic of a high-pressure space discharge with external gas ionization

A one-dimensional theoretical model of high-pressure gas discharge with an external ionizer is constructed in the present work. The model can be used to calculate the continuous current-voltage characteristic of the discharge with an external ionizer for any arbitrary current density from values close to zero when the discharge is non-self-maintained to values typical of normal and slightly anomalous glow discharges. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 37–41, August, 2007.     

Instability of the magnetization reversal front in superconductors with a nonlinear anisotropic current-voltage characteristic

The instability of a magnetic flux flow in a system of vortices and antivortices in superconductors with a power (exponent m) anisotropic current-voltage characteristic was studied theoretically. It was shown that instability arose even at a comparatively weak anisotropy of the current-carrying properties of a superconductor if m?1. The dispersion equation determining the dependence of the increment of instability growth on the wave number was derived and analyzed.