Searcharxiv⌕ Search

arXiv subjects

I. L. Aleiner

Publications and source records attributed to I. L. Aleiner.

At least 55 records · Page 3Linked to original sources
arXiv2003

Two dimensional electron gas near full polarization

We establish the consistency of the Fermi liquid description and find a relation between Fermi liquid constants for the two dimensional electron system near the point of full polarization due to a parallel magnetic field $H$. Our results enable us to predict connections between different thermodynamic properties of the system. In particular, we find that near the point of full polarization $H_c$, the thermodynamic compressibility of the system experiences a jump with the subleading $(H_c-H)^{1/2}$ dependence on the magnetic field. Also, the magnetization has a cusp with the dependence of the type $(H-H_c) + (H_c-H)^{3/2}$ at $H<H_c$.

cond-mat.mes-hall↗
arXiv2003

Dynamical symmetry breaking as the origin of the zero-$dc$-resistance state in an $ac$-driven system

Under a strong $ac$ drive the zero-frequency linear response dissipative resistivity $ρ_{d}(j=0)$ of a homogeneous state is allowed to become negative. We show that such a state is absolutely unstable. The only time-independent state of a system with a $ρ_{d}(j=0)<0$ is characterized by a current which almost everywhere has a magnitude $j_{0}$ fixed by the condition that the nonlinear dissipative resistivity $ρ_{d}(j_{0}^{2})=0$. As a result, the dissipative component of the $dc$ electric field vanishes. The total current may be varied by rearranging the current pattern appropriately with the dissipative component of the $dc$-electric field remaining zero. This result, together with the calculation of Durst \emph{et. al.}, indicating the existence of regimes of applied $ac$ microwave field and $dc$ magnetic field where $ρ_{d}(j=0)<0$, explains the zero-resistance state observed by Mani \emph{et. al.} and Zudov \emph{et. al.}.

cond-mat.mes-hall↗
arXiv2003

On the Applicability of the Ergodicity Hypothesis to Mesoscopic Fluctuations

We evaluate a typical value of higher order cumulants (irreducible moments) of conductance fluctuations that could be extracted from magneto-conductance measurements in a single sample when an external magnetic field is swept over an interval $B_0$. We find that the n-th cumulant has a sample-dependent random part $\pm \gN 2^{n/2}\sqrt{a_{n}B_{c}/B_{0}}$, where $\gN 2$ is the variance of conductance fluctuations, $B_{c}$ is a correlation field, and $a_{n}\sim n!$. This means that an apparent deviation of the conductance distribution from a Gaussian shape, manifested by non-vanishing higher cumulants, can be a spurious result of correlations of conductances at different values of the magnetic field.

cond-mat.mes-hall↗
arXiv2002

Non-existence of strong coupling two-channel Kondo fixed point for microscopic models of tunneling centers

We consider the problem of an heavy particle in a double well potential (DWP) interacting with an electron bath. Under general assumptions, we map the problem to a three-color logarithmic gas model, where the size of the core of the charged particles is proportional to the tunneling time, $τ_{tun}$, of the heavy particle between the two wells. For times larger then $τ_{tun}$ this model is equivalent to the anisotropic two-channel Kondo (2CK) model in a transverse field. This allows us to establish a relationship between the microscopic parameters of DWP and the 2CK problem. We show that the strong coupling fixed point of the 2CK model can never be reached for the DWP problem, in agreement with the results of Kagan and Prokof'ev, [Sov.Phys. JEPT, 69, 836 (1989)] and Aleiner et al., [Phys. Rev. Lett. 86, 2629 (2001)].

cond-mat.dis-nn↗
arXiv2002

Coulomb "blockade" of Nuclear Spin Relaxation in Quantum Dots

We study the mechanism of nuclear spin relaxation in quantum dots due to the electron exchange with 2D gas. We show that the nuclear spin relaxation rate is dramatically affected by the Coulomb blockade and can be controlled by gate voltage. In the case of strong spin-orbit coupling the relaxation rate is maximal in the Coulomb blockade valleys whereas for the weak spin-orbit coupling the maximum of the nuclear spin relaxation rate is near the Coulomb blockade peaks.

cond-mat.mes-hall↗
arXiv2002

Interaction corrections at intermediate temperatures: dephasing time

We calculate the temperature dependence of the weak localization correction in a two dimensional system at arbitrary relation between temperature, $T$ and the elastic mean free time. We describe the crossover in the dephasing time ${τ_ϕ(T)}$ between the high temperature, $1/τ_ϕ\simeq T^2 \ln T$, and the low temperature $1/τ_ϕ\simeq T$ behaviors. The prefactors in these dependences are not universal, but are determined by the Fermi liquid constant characterising the spin exchange interaction.

cond-mat.dis-nn↗
arXiv2001

Quantum Effects in Coulomb Blockade

We review the quantum interference effects in a system of interacting electrons confined to a quantum dot. The review starts with a description of an isolated quantum dot. We discuss the status of the Random Matrix theory (RMT) of the one-electron states in the dot, present the universal form of the interaction Hamiltonian compatible with the RMT, and derive the leading corrections to the universal interaction Hamiltonian. Next, we discuss a theoretical description of a dot connected to leads via point contacts. Having established the theoretical framework to describe such an open system, we discuss its transport and thermodynamic properties. We review the evolution of the transport properties with the increase of the contact conductances from small values to values $\sim e^2/π\hbar$. In the discussion of transport, the emphasis is put on mesoscopic fluctuations and the Kondo effect in the conductance.

cond-mat.mes-hall↗
arXiv2001

Interaction corrections at intermediate temperatures: magneto-resistance in parallel field

We consider the correction to conductivity of a 2D electron gas due to electron-electron interaction in the parallel magnetic field at arbitrary relation between temperature and the elastic mean free time. The correction exhibits non-trivial dependence on both temperature and the field. This dependence is determined by the Fermi liquid constant, which accounts for the spin-exchange interaction. In particular, the sign of the slope of the temperature dependence is not universal and can change with the increase of the field.

cond-mat.dis-nn↗
arXiv2001

Interaction corrections at intermediate temperatures: I. Longitudinal conductivity and kinetic equation

It is well known that electron-electron interaction in disordered systems leads to logarithmically divergent Altshuler-Aronov corrections to conductivity at low temperatures ($Tτ\ll 1$; $τ$ is the elastic mean-free time). This paper is devoted to the fate of such corrections at intermediate temperatures $Tτ\ge 1$. We show that in this (ballistic) regime the temperature dependence of conductivity is still governed by the same physical processes as the Altshuler-Aronov correction - scattering by Friedel oscillations. However, in this regime the correction is linear in temperature; the value and even the {\em sign} of the slope depends on the strength of electron-electron interaction. We show that the slope is directly related to the renormalization of the spin susceptibility and grows as the system approaches the ferromagnetic Stoner instability. Also, we obtain the temperature dependence of the conductivity in the cross-over region between the diffusive and the ballistic regimes. Finally, we derive the quantum kinetic equation, which describes electron transport for arbitrary value of $Tτ$.

cond-mat↗
arXiv2001

Interaction corrections to the Hall coefficient at intermediate temperatures

We investigate the effect of electron-electron interaction on the temperature dependence of the Hall coefficient of 2D electron gas at arbitrary relation between the temperature $T$ and the elastic mean-free time $τ$. At small temperature $Tτ\ll \hbar$ we reproduce the known relation between the logarithmic temperature dependences of the Hall coefficient and of the longitudinal conductivity. At higher temperatures, this relation is violated quite rapidly; correction to the Hall coefficient becomes $\propto 1/T$ whereas the longitudinal conductivity becomes linear in temperature.

cond-mat.dis-nn↗
arXiv2001

Spin-orbit coupling effects on quantum transport in lateral semiconductor dots

The effects of interplay between spin-orbit coupling and Zeeman splitting on weak localisation and universal conductance fluctuations in lateral semiconductor quantum dots are analysed: All possible symmetry classes of corresponding random matrix theories are listed and crossovers between them achievable by sweeping magnetic field and changing the dot parameters are described. We also suggest experiments to measure the spin-orbit coupling constants.

cond-mat.mes-hall↗
arXiv2001

Inelastic Scattering Time for Conductance Fluctuations

We revisit the problem of inelastic times governing the temperature behavior of the weak localization correction and mesoscopic fluctuations in one- and two-dimensional systems. It is shown that, for dephasing by the electron electron interaction, not only are those times identical but the scaling functions are also the same.

cond-mat.mes-hall↗
arXiv2001

On the critical temperature of two-channel Kondo model: Reply to cond-mat/0009283

We discuss the comment by Zarand and Zawadowski (cond-mat/0009283) on our preprint cond-mat/0007430 where it has been shown that the strong coupling regime for the two-channel Kondo model of two level system can be never realized for any realistic microscopic description. The authors of the comment state that the Kondo temperature can be substantially increased due to electron-hole asymmetry. Here we show by direct calculation that the electron-hole asymmetry does not enter the leading logarithmic approximation. Consequently, we disagree with the aforementioned comment.

cond-mat.mes-hall↗
arXiv2000

Mesoscopic fluctuations of the Coulomb drag at $ν$=1/2

We consider mesoscopic fluctuations of Coulomb drag transresistivity between two layers at a Landau level filling factor $ν=1/2$ each. We find that at low temperature sample to sample fluctuations exceed both the ensemble average and the corresponding fluctuations at B=0. At the experimentally relevant temperatures, the variance of the transresistivity is proportional to $T^{-1/2}$. We find the dependence of this variance on density and magnetic field to reflect the attachment of two flux quanta to each electron.

cond-mat.mes-hall↗
arXiv2000

Ground state spin and Coulomb blockade peak motion in chaotic quantum dots

We investigate experimentally and theoretically the behavior of Coulomb blockade (CB) peaks in a magnetic field that couples principally to the ground-state spin (rather than the orbital moment) of a chaotic quantum dot. In the first part, we discuss numerically observed features in the magnetic field dependence of CB peak and spacings that unambiguously identify changes in spin S of each ground state for successive numbers of electrons on the dot, N. We next evaluate the probability that the ground state of the dot has a particular spin S, as a function of the exchange strength, J, and external magnetic field, B. In the second part, we describe recent experiments on gate-defined GaAs quantum dots in which Coulomb peak motion and spacing are measured as a function of in-plane magnetic field, allowing changes in spin between N and N+1 electron ground states to be inferred.

cond-mat.mes-hall↗
arXiv2000

Experimental tests for the relevance of two-level systems for electron dephasing

The relevance of tunneling two-level systems (TLS) for electron dephasing in metals is analyzed. We demonstrate that if the concentration of TLS is sufficient to cause the observed dephasing rate, one also should expect quite substantial effects in the specific heat and ultrasound attenuation. In both cases TLS contribution should dominate the electronic one at low enough temperatures.

cond-mat.mes-hall↗