Luttinger liquid and polaronic effects in electron transport through a molecular transistor

Electron transport through a single-level quantum weakly dot coupled to Luttinger liquid leads is considered in the master equation approach. It is shown that for a weak or moderately strong interaction the differential conductance demonstrates resonant-like behavior as a function of bias and gate voltages. The inelastic channels associated with vibron-assisted electron tunnelling can even dominate electron transport for a certain region of interaction strength. In the limit of strong interaction resonant behavior disappears and the differential conductance scales as a power low on temperature (linear regime) or on bias voltage (nonlinear regime)

Polaronic effects in electron shuttling

Shuttle-like mechanism of electron transport through a single level vibrating quantum dot is considered in the regime of strong electromechanical coupling. It is shown that the increment of shuttle instability is a nonmonotonic function of the driving voltage. The interplay of two oppositively acting effects—vibron-assisted electron tunneling and polaronic blockade — results in oscillations of the increment on the energy scale of vibron energy

Manifestation of polaronic effects in Josephson currents

Polaronic effects on the Josephson current through a vibrating quantum dot are considered. In the regime of strong electron–vibron interactions they lead to a power-law suppression of the critical current. This is manifested in an anomalous temperature dependence of the critical current at temperatures of the order of the polaronic energy shift

Graphene and graphene-based nanostructures

This issue of the journal «Fizika Nizkikh Temperatur» is dedicated to the discovery of graphene — a monolayer graphite — in 2004

Carbon «peapods» – a new tunable nanoscale graphitic structure (Review Article)

We consider the ectronic properties of empty single-wall nanotubes (SWNT) and SWNT filled with the fullerenle molecules (carbon «nano-peapod»). The first part of the review (section 2) is devoted mostly to the Luttinger liqued properties of individual metallic SWNT coupled to metallic electrodes or to superconducting leads. The discovery of carbon «nano-peapods» and their elastic, electric and thermal properties are reviewed in the second part of the paper (section 3). We suggest in particularly how fullerene and metallofullerene molecules can be raleased from a «nano-peapod» by a purely electrostatic method

Giant magnetization of a superconductor–two-dimensional electron gas–superconductor structure

Superconductivity induced phase-controlled mesoscopic magnetic effects in a two-dimensional electron gas that bridges two superconducting reservoirs are investigated. Giant paramagnetic response of the junction, occuring at certain values of the phase difference of the order parameter, is predicted. A geometrically similar system, consisting of a graphene ribbon stretched between two superconducting leads, is also considered. The magnetic effects in this system are found to be small and the difference between the magnetic properties of the two systems is discussed

Low-energy anomalies in electron tunneling through strongly asymmetric Majorana nanowire

Electron transport through Majorana nanowire with strongly asymmetric couplings to normal metal leads is considered. In three terminal geometry (electrically grounded nanowire) it is shown that the presence of unbiased electrode restores zero-bias anomaly even for strong Majorana energy splitting. For effectively two-terminal geometry we show that electrical current through asymmetric Majorana junction is qualitatively different from the analogous current through a resonant (Breit–Wigner) level

Charge and spin effects in mesoscopic Josephson junctions (Review Article)

We consider the charge and spin effects in low dimensional superconducting weak links. The first part of the review deals with the effects of electron—electron interaction in Superconductor/ Luttinger liquid/Superconductor junctions. The experimental realization of this mesoscopic hybrid system can be the individual single wall carbon nanotube that bridges the gap between two bulk superconductors. The dc Josephson current through a Luttinger liquid is evaluated in the limits of perfectly and poorly transmitting junctions. The relationship between the Josephson effect in a long SNS junction and the Casimir effect is discussed. In the second part of the paper we review the recent results concerning the influence of the Zeeman and Rashba interactions on the thermodynamical properties of ballistic S–QW–S junction fabricated in two dimensional electron gas. It is shown that in magnetically controlled junction there are conditions for resonant Cooper pair transition which results in giant supercurrent through a tunnel junction and a giant magnetic response of a multichannel SNS junction. The supercurrent induced by the joint action of the Zeeman and Rashba interactions in 1D quantum wires connected to bulk superconductors is predicted

Superconducting phase-dependent force in SNS junctions with a movable scatterer

We calculate a quantum (Casimir-like) superconducting phase-dependent force acting on a movable scatterer in a superconductor–normal metal–superconductor (SNS) junction. Repulsive Casimir forces are predicted for a short SNS junction with nonequilibrium (inverse) populations of Andreev levels. In a long SNS junction an anomalous (nonmonotonic) temperature behavior of quantum force is found

Resonant tunneling of electrons in quantum wires

We considered resonant electron tunneling in various nanostructures including single wall carbon nanotubes, molecular transistors and quantum wires formed in two-dimensional electron gas. The review starts with a textbook description of resonant tunneling of noninteracting electrons through a double-barrier structure. The effects of electron–electron interaction in sequential and resonant electron tunneling are studied by using Luttinger liquid model of electron transport in quantum wires. The experimental aspects of the problem (fabrication of quantum wires and transport measurements) are also considered. The influence of vibrational and electromechanical effects on resonant electron tunneling in molecular transistors is discussed