arXiv subjects

E. G. Mishchenko

Publications and source records attributed to E. G. Mishchenko.

64 records · Page 4Linked to original sources

arXiv2002

Full counting statistics of a charge pump in the Coulomb blockade regime

We study the full charge counting statistics of a charge pump based on a nearly open single electron transistor. The problem is mapped onto an exactly soluble problem of a g=1/2 non-equilibrium Luttinger liquid with an impurity. We obtain an analytic expression for the generating function of the transmitted charge for an arbitrary pumping strength. Even though this model contains fractionally charged excitations only integer transmitted charges can be observed during finite observation times.

cond-mat.mes-hall↗

arXiv2001

Zero-bias anomaly in disordered wires

We calculate the low-energy tunneling density of states $ν(ε, T)$ of an $N$-channel disordered wire, taking into account the electron-electron interaction non-perturbatively. The finite scattering rate $1/τ$ results in a crossover from the Luttinger liquid behavior at higher energies, $ν\proptoε^α$, to the exponential dependence $ν(ε, T=0)\propto \exp{(-ε^*/ε)}$ at low energies, where $ε^*\propto 1/(N τ)$. At finite temperature $T$, the tunneling density of states depends on the energy through the dimensionless variable $ε/\sqrt{ε^* T}$. At the Fermi level $ν(ε=0,T) \propto \exp (-\sqrt{ε^*/T})$.

cond-mat.mes-hall↗

arXiv2001

Zero-bias anomaly in two-dimensional electron layers and multiwall nanotubes

The zero-bias anomaly in the dependence of the tunneling density of states $ν(ε)$ on the energy $ε$ of the tunneling particle for two- and one-dimensional multilayered structures is studied. We show that for a ballistic two-dimensional (2D) system the first order interaction correction to DOS due to the plasmon excitations studied by Khveshchenko and Reizer is partly compensated by the contribution of electron-hole pairs which is twice as small and has the opposite sign. For multilayered systems the total correction to the density of states near the Fermi energy has the form $δν/ν_0 = {max} (| ε|, ε^*)/4ε_F$, where $ε^*$ is the plasmon energy gap of the multilayered 2D system. In the case of one-dimensional conductors we study multiwall nanotubes with the elastic mean free path exceeding the radius of the nanotube. The dependence of the tunneling density of states energy, temperature and on the number of shells is found.

cond-mat.mes-hall↗

arXiv2000

Nonlinear voltage dependence of the shot noise in mesoscopic degenerate conductors with strong electron-electron scattering

It is shown that measurements of zero-frequency shot-noise can provide information on electron-electron interaction, because the strong interaction results in the nonlinear voltage dependence of the shot noise in metallic wires. This is due to the fact that the Wiedemann-Franz law is no longer valid in the case of considerable electron-electron interaction. The deviations from this law increase the noise power and make it dependent strongly on the ratio of electron-electron and electron-impurity scattering rates.

cond-mat.mes-hall↗

arXiv2000

Frequency dependence of the photonic noise spectrum in an absorbing or amplifying diffusive medium

A theory is presented for the frequency dependence of the power spectrum of photon current fluctuations originating from a disordered medium. Both the cases of an absorbing medium (``grey body'') and of an amplifying medium (``random laser'') are considered in a waveguide geometry. The semiclassical approach (based on a Boltzmann-Langevin equation) is shown to be in complete agreement with a fully quantum mechanical theory, provided that the effects of wave localization can be neglected. The width of the peak in the power spectrum around zero frequency is much smaller than the inverse coherence time, characteristic for black-body radiation. Simple expressions for the shape of this peak are obtained, in the absorbing case, for waveguide lengths large compared to the absorption length, and, in the amplifying case, close to the laser threshold.

cond-mat.mes-hall↗

arXiv1999

Radiative transfer theory for vacuum fluctuations

A semiclassical kinetic theory is presented for the fluctuating photon flux emitted by a disordered medium in thermal equilibrium. The kinetic equation is the optical analog of the Boltzmann-Langevin equation for electrons. Vacuum fluctuations of the electromagnetic field provide a new source of fluctuations in the photon flux, over and above the fluctuations due to scattering. The kinetic theory in the diffusion approximation is applied to the super-Poissonian noise due to photon bunching and to the excess noise due to beating of incident radiation with the vacuum fluctuations.

cond-mat.mes-hall↗

arXiv1999

Shot-noise in non-degenerate semiconductors with energy-dependent elastic scattering

We investigate current fluctuations in non-degenerate semiconductors, on length scales intermediate between the elastic and inelastic mean free paths. The shot-noise power P is suppressed below the Poisson value P_{\rm Poisson}=2e\bar I (at mean current \bar I) by the Coulomb repulsion of the carriers. We consider a power-law dependence of the elastic scattering time τ\proptoε^α on kinetic energy εand present an exact solution of the non-linear kinetic equations in the regime of space-charge limited conduction. The ratio P/P_{\rm Poisson} decreases from 0.38 to 0 in the range -1/2 < α< 1.

cond-mat.mes-hall↗

arXiv1999

Raman scattering in a two-dimensional electron gas: Boltzmann equation approach

The inelastic light scattering in a 2-d electron gas is studied theoretically using the Boltzmann equation techniques. Electron-hole excitations produce the Raman spectrum essentially different from the one predicted for the 3-d case. In the clean limit it has the form of a strong non-symmetric resonance due to the square root singularity at the electron-hole frequency $ω= vk$ while in the opposite dirty limit the usual Lorentzian shape of the cross section is reestablished. The effects of electromagnetic field are considered self-consistently and the contribution from collective plasmon modes is found. It is shown that unlike 3-d metals where plasmon excitations are unobservable (because of very large required transfered frequencies), the two-dimensional electron system gives rise to a low-frequency ($ω\propto k^{1/2}$) plasmon peak. A measurement of the width of this peak can provide data on the magnitude of the electron scattering rate.

cond-mat.mes-hall↗

arXiv1999

Electron-lattice kinetics of metals heated by ultrashort laser pulses

We propose a kinetic model of transient nonequilibrium phenomena in metals exposed to ultrashort laser pulses when heated electrons affect the lattice through direct electron-phonon interaction. This model describes the destruction of a metal under intense laser pumping. We derive the system of equations for the metal, which consists of hot electrons and a cold lattice. Hot electrons are described with the help of the Boltzmann equation and equation of thermoconductivity. We use the equations of motion for lattice displacements with the electron force included. The lattice deformation is estimated immediately after the laser pulse up to the time of electron temperature relaxation. An estimate shows that the ablation regime can be achieved.

cond-mat.stat-mech↗

arXiv1999

Kinetic theory of shot noise in non-degenerate diffusive conductors

We investigate current fluctuations in non-degenerate semiconductors, on length scales intermediate between the elastic and inelastic mean free paths. We present an exact solution of the non-linear kinetic equations in the regime of space-charge limited conduction, without resorting to the drift approximation of previous work. By including the effects of a finite voltage and carrier density in the contact region, a quantitative agreement is obtained with Monte Carlo simulations by Gonz{á}lez et al., for a model of an energy-independent elastic scattering rate. The shot-noise power $P$ is suppressed below the Poisson value $P_{Poisson}=2e\bar I$ (at mean current $\bar I$) by the Coulomb repulsion of the carriers. The exact suppression factor is close to 1/3 in a three-dimensional system, in agreement with the simulations and with the drift approximation. Including an energy dependence of the scattering rate has a small effect on the suppression factor for the case of short-range scattering by uncharged impurities or quasi-elastic scattering by acoustic phonons. Long-range scattering by charged impurities remains an open problem.

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