S. N. Artemenko, P. P. Aseev, D. S. Shapiro, R. R. Vakhitov
We study theoretically electron transport in a 1D conductor with an isolated local defect such as an impurity or a non-adiabatic contact. We predict a new regime of transport in which the dc current $\bar I$ is accompanied by ac oscillations of frequency $f = \bar I/e$. The effect is related to interaction of the current in the wire with Friedel oscillations of electronic density produced by the defect. Manifestations of the effect resemble the Coulomb blockade and the Josephson effect. We study the role of fluctuations and their effect on I-V curves in the dynamic regime of conduction. 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. Threshold voltage is determined by $2k_F$-component of impurity potential renormalized by fluctuations. 1D conductor is described in terms of the Luttinger liquid with short range or long-range Coulomb interaction. 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 in case of spin-rotation invariant interaction. We find also that a spin bias applied to the system contributes to electric current, and this is related to violation of the spin-charge separation at the defect site.
View original:
http://arxiv.org/abs/1203.5203
No comments:
Post a Comment