arXiv subjects

S. N. Artemenko

Publications and source records attributed to S. N. Artemenko.

At least 19 recordsLinked to original sources

arXiv2015

Electronic transport through a correlated quantum wire connected to a superconducting lead

We study theoretically the electron transport in a 1D conductor adiabatically connected to a superconducting and normal metal leads. In the case of non-interacting we show that ac voltage applied along with dc voltage modifies I-V curve resembling a regime of photon-assisted tunneling. We obtain in the limit of low voltages, that the electron-electron interaction affects electronic transport resulting in a decrease of conductance and features in the frequency dependence of the impedance.

cond-mat.mes-hall↗

arXiv2013

Dynamical regime of electron transport in correlated one-dimensional conductor with defect

The electron transport in a 1D conductor with an isolated local defect such as an impurity or a non-adiabatic contact is studied theoretically. New regime of conduction in correlated 1D systems is predicted beyond the well-known regime of tunneling resulting in the power-law I-V-curves. In this regime a quantum wire becomes "opened" at voltage biases above the threshold value $V_T$, giving rise to a rapid increase of the dc current, $\bar I$, accompanied by ac oscillations of frequency $f = \bar I/e$. The effect of ac generation is related to sliding of the Friedel oscillations of electronic density produced by the defect. Manifestations of the effect resemble the Coulomb blockade and the Josephson effect. The spin bias applied to the system is shown to affect the I-V curves due to violation of the spin-charge separation at the defect site. In short quantum wires of length $L < L_0 \sim \hbar v_F/eV_T$ and at high temperatures $T > T_0 \sim eV_T/k_B$ the effect is destroyed by fluctuations. The threshold voltage $V_T$ is determined by $2k_F$-component of impurity potential renormalized by fluctuations. The 1D conductor is described in terms of the Tomonaga-Luttinger Hamiltonian with short range or long-range Coulomb interaction by means of the bosonization technique. We derive boundary conditions that take into account relaxation in the leads and permit to solve non-equilibrium problems. Charge fluctuations are studied by means of Gaussian model which can be justified strictly in the limit of large voltages or strong enough inter-electronic repulsion. Spin fluctuations are taken into account strictly by means of the refermionization technique applicable in case of spin-rotation invariant interaction.

cond-mat.str-el↗

arXiv2013

Spin injection from topological insulator tunnel-coupled to metallic leads

We study theoretically helical edge states of 2D and 3D topological insulators (TI) tunnel-coupled to metal leads and show that their transport properties are strongly affected by contacts as the latter play a role of a heat bath and induce damping and relaxation of electrons in the helical states of TI. A simple structure that produces a pure spin current in the external circuit is proposed. The current and spin current delivered to the external circuit depend on relation between characteristic lengths: damping length due to tunneling, contact length and, in case of 3D TI, mean free path and spin relaxation length caused by momentum scattering. If the damping length due to tunneling is the smallest one, then the electric and spin currents are proportional to the conductance quantum in 2D TI, and to the conductance quantum multiplied by the ratio of the contact width to the Fermi wavelength in 3D TI.

cond-mat.mes-hall↗

arXiv2012

Photogalvanic effects in topological insulators

We discuss optical absorption in topological insulators and study possible photoelectric effects theoretically. We found that absorption of circularly polarized electromagnetic waves in two-dimensional topological insulators results in electric current in the conducting 1D edge channels, the direction of the current being determined by the light polarization. We suggest two ways of inducing such a current: due to magnetic dipole electron transitions stimulated by irradiation of frequency below the bulk energy gap, and due to electric dipole transitions in the bulk at frequencies larger than the energy gap with subsequent capture of the photogenerated carriers on conducting edge states.

cond-mat.mes-hall↗

arXiv2011

Stabilization of the surface CDW order parameter by long-range Coulomb interaction

We study theoretically formation of two-dimensional (2D) charge density wave (CDW) in a system of conducting chains at the surface of an insulator due to interaction of quasi 1D surface electrons with phonons. We show that the unscreened long-range Coloumb interaction between the charges induced by fluctuations of the CDW phase stabilizes the finite order parameter value at finite temperatures, and thus the long-range order (LRO) exists. In the case of screened Coloumb interaction the phase fluctuations suppress the phase transition, but decay of the order parameter is rather slow, it obeys a power-law $<Δ^*(r) Δ(0)> \propto r^{-γ}$ with small exponent $γ$

cond-mat.mes-hall↗

arXiv2010

Electronic transport through a contact of a correlated quantum wire with leads of higher dimension

We study theoretically electronic transport through a contact of a quantum wire with 2D or 3D leads and find that if the contact is not smooth and adiabatic then the conduction is strongly suppressed below a threshold voltage $V_T$, while above $V_T$ the dc current $\bar I$ is accompanied by coherent oscillations of frequency $f=\bar I / e$. The effect is related to interelectronic repulsion and interaction of dc current with the Friedel oscillations near a sharp contact. In short conducting channels of length $L < L_0 \simeq \hbar v_F/eV_T$ and at high temperatures $T > T_0 \simeq eV_T/k_B$ the effect is destroyed by fluctuations.

cond-mat.mes-hall↗

arXiv2008

Effect of impurity pinning on conduction and specific heat in the Luttinger liquid

We study theoretically two effects related to impurity depinning that are common for 1D Luttinger liquid (LL) and linear-chain CDW conductors. First, we consider the electron transport through a single impurity in a 1D conducting channel and study a new regime of conduction related to LL sliding at voltage above a threshold one. The DC current in this regime is accompanied by oscillations with frequency $f =I/e$. This resembles the CDW depinning in linear-chain conductors, the Josephson effect, and the Coulomb blockade. Second, we found that strong pinning of the LL by impurities leads to a magnetic field dependence of the low-temperature specific heat similar to that observed experimentally in CDW compounds. We interpret this in favor of possibility of formation of the LL in linear-chain compounds.

cond-mat.str-el↗

arXiv2008

Impurity induced coherent current oscillations in one-dimensional conductors

We study theoretically the electronic transport through a single impurity in a repulsive Luttinger liquid (LL), and find that above a threshold voltage related to a strength of the impurity potential the DC current $\bar I$ is accompanied by coherent oscillations with frequency $f = \bar I/e$. There is an analogy with Josephson junctions: the well-known regime of power-law I-V curves in the LL corresponds to damping of the Josephson current below the critical one, while the oscillatory regime in the LL can be compared with the Josephson oscillations above the critical current.

cond-mat.mes-hall↗

arXiv2007

Long-range order in quasi-one-dimensional conductors

We study formation of the charge-density wave long-range order in a system of repulsive 1D electrons coupled to 3D phonons. We show that the CDW can be stabilized by interaction with phonons in quasi-1D crystals and semiconducting nanowires. In the case of metallic atomic chains, interaction with phonons of 3D substrate is not enough, and violation of the translational invariance by commensurable perturbation or disorder is needed. The possibility of stabilization of superconductivity in 1D electrons with attraction by means of tunnel coupling to a 3D metal is considered.

cond-mat.str-el↗

arXiv2005

Low-temperature conductivity of quasi-one-dimensional conductors: Luttinger liquid stabilized by impurities

A new non-Fermi-liquid state of quasi-one-dimensional conductors is suggested in which electronic system exists in a form of collection of bounded Luttinger liquids stabilized by impurities. This state is shown to be stable towards interchain electron hopping at low temperatures. Electronic spectrum of the system contains zero modes and collective excitations of the bounded Luttinger liquids in the segments between impurities. Zero modes give rise to randomly distributed localized electronic levels, and long-range interaction generates the Coulomb gap in the density of states at the Fermi energy. Mechanism of conductivity at low temperatures is phonon-assisted hopping via zero-mode states. At higher voltages the excitations of Luttinger liquid are involved in electron transport, and conductivity obeys power-law dependence on voltage. The results provide a qualitative explanation for recent experimental data for NbSe3 and TaS3 crystals.

cond-mat.str-el↗

arXiv2005

High-frequency oscillations in low-dimensional conductors and semiconductor superlattices induced by current in stack direction

A narrow energy band of the electronic spectrum in some direction in low-dimensional crystals may lead to a negative differential conductance and N-shaped I-V curve that results in an instability of the uniform stationary state. A well-known stable solution for such a system is a state with electric field domain. We have found a uniform stable solution in the region of negative differential conductance. This solution describes uniform high-frequency voltage oscillations. Frequency of the oscillation is determined by antenna properties of the system. The results are applicable also to semiconductor superlattices.

cond-mat.str-el↗

arXiv2004

Impurity-induced stabilization of Luttinger liquid in quasi-one-dimensional conductors

It is shown theoretically that the Luttinger liquid phase in quasi-one-dimensional conductors can exist in the presence of impurities in a form of a collection of bounded Luttinger liquids. The conclusion is based upon the observation by Kane and Fisher that a local impurity potential in Luttinger liquid acts, at low energies, as an infinite barrier. This leads to a discrete spectrum of collective charge and spin density fluctuations, so that interchain hopping can be considered as a small parameter at temperatures below the minimum excitation energy of the collective modes. The results are compared with recent experimental observation of a Luttinger-liquid-like behavior in thin NbSe$_3$ and TaS$_3$ wires.

cond-mat.str-el↗

arXiv2003

Friedel oscillations in a gas of interacting one-dimensional fermionic atoms confined in a harmonic trap

Using an asymptotic phase representation of the particle density operator $\hatρ(z)$ in the one-dimensional harmonic trap, the part $δ\hatρ_F(z)$ which describes the Friedel oscillations is extracted. The expectation value $<δ\hatρ_F(z)>$ with respect to the interacting ground state requires the calculation of the mean square average of a properly defined phase operator. This calculation is performed analytically for the Tomonaga-Luttinger model with harmonic confinement. It is found that the envelope of the Friedel oscillations at zero temperature decays with the boundary exponent $ν= (K+1)/2$ away from the classical boundaries. This value differs from that known for open boundary conditions or strong pinning impurities. The soft boundary in the present case thus modifies the decay of Friedel oscillations. The case of two components is also discussed.

cond-mat.str-el↗

arXiv2002

Stability of Driven Josephson Vortex Lattice in Layered Superconductors Revisited

We analytically study stability of sliding lattice of Josephson vortices driven by a transport current in the stack direction in strong in-plane magnetic field. In contrast to recent findings we obtain that there are no diverse configurations of stable vortex lattices, and, hence, the stable sliding vortex lattice can not be selected by boundary conditions. We find that only the triangular (rhombic) lattice can be stable, its stability being limited by a critical velocity value. At higher velocities there are no simple stable lattices with single flux line per unit cell. Oblique sliding lattices are found to be never stable. Instability of such lattices is revealed beyond the linear approximation in perturbations of the lattice.

cond-mat.supr-con↗

arXiv2001

Coulomb Effects in Spectral Density and Transverse Conductivity of Layered Metals

Renormalization of the Coulomb interaction in layered metals results in a strongly anisotropic plasma mode with low frequencies for small components of wave vector in the in-plane direction. Interaction of electrons with this mode was found to lead to an incoherent contribution to the electron spectral density which spreads up to large energies. In the superconducting state this reproduces the peak-dip-hump feature similar to that observed in layered high-T$_c$ superconductors. The incoherent part of the spectral density and plasmon-assisted electron transitions provide mechanisms for nearly linear conductivity in the stack direction at large voltages or frequencies.

cond-mat.supr-con↗

arXiv2001

Negative Resistance and Local Charge-Density-Wave Dynamics

Charge-density-wave dynamics is studied on a submicron length scale in NbSe_3 and o-TaS_3. Regions of negative absolute resistance are observed in the CDW sliding regime at sufficiently low temperatures. The origin of the negative resistance is attributed to the different forces that the deformed CDW and quasi-particles feel: the force on the CDW is merely caused by a difference of the electric potentials, while the quasi-particle current is governed by a difference of the electrochemical potentials.

cond-mat.str-el↗

arXiv2000

On Effect of Equilibrium Fluctuations on Superfluid Density in Layered Superconductors

We calculate suppression of inter- and intralayer superconducting currents due to equilibrium phase fluctuations and find that, in contrast to a recent prediction, the effect of thermal fluctuations cannot account for linear temperature dependence of the superfluid density in high-Tc superconductors at low temperatures. Quantum fluctuations are found to dominate over thermal fluctuations at low temperatures due to hardening of their spectrum caused by the Josephson plasma resonance. Near Tc sizeable thermal fluctuations are found to suppress the critical current in the stack direction stronger, than in the direction along the layers. Fluctuations of quasiparticle branch imbalance make the spectral density of voltage fluctuations at small frequencies non zero, in contrast to what may be expected from a naive interpretation of Nyquist formula.

cond-mat.supr-con↗

arXiv2000

Convective Term and Transversely Driven Charge-Density Waves

We derive the convective terms in the damping which determine the structure of the moving charge-density wave (CDW), and study the effect of a current flowing transverse to conducting chains on the CDW dynamics along the chains. In contrast to a recent prediction we find that the effect is orders of magnitude smaller, and that contributions from transverse currents of electron- and hole-like quasiparticles to the force exerted on the CDW along the chains act in the opposite directions. We discuss recent experimental verification of the effect and demonstrate experimentally that geometry effects might mimic the transverse current effect.

cond-mat.str-el↗