Nonohmic Coulomb drag in the ballistic electron transport regime

Abstract

We work out a theory of the Coulomb drag current created under the ballistic transport regime in a one-dimensional nanowire by a ballistic non-Ohmic current in a nearby parallel nanowire. As in the Ohmic case, we predict sharp oscillation of the drag current as a function of gate voltage or the chemical potential of electrons. We also study dependence of the drag current on the voltage V across the driving wire. For relatively large values of V the drag current is proportional to V 2 .The purpose of the present paper is to study the Coulomb drag current in the course of ballistic (collisionless) electron transport in a nanowire due to a ballistic driving non-Ohmic current in an adjacent parallel nanowire. The possibility of the Coulomb drag effect in the ballistic regime in quantum wires has been demonstrated by Gurevich, Pevzner and Fenton [1]1 and has been experimentally observed by Debray et al. [2]. If two wires, 1 and 2, are near one another and are parallel, the drag force due to the ballistic current in wire 2 acts as a sort of permanent acceleration on the electrons of wire 1 via the Coulomb interaction.We assume that the largest dimension of the structure is smaller than the electron mean free path in the problem (typically a few µm). Such nanoscale systems are characterized by low electron densities, which may be varied by means of the gate voltage.1 A number of references to early papers on the Coulomb drag is given in [1].

Experimental studies of Coulomb drag between ballistic quantum wires

“…More surprising is the sublinear behaviour of V D for V DS > 350 µV. The FL theory of the CD predicts a superlinear behaviour [21] R D ∼ V 2…”

Coulomb drag between one-dimensional Wigner crystal rings

“…Recently, the phenomenon of Coulomb drag in one dimensional systems has attracted much attention, particularly with regards to nanowires and nanotechnology 7,8,9, 10,11 . The basic description of the one dimensional case is identical to that in two dimensions.…”

Phonon drag in ballistic quantum wires in the nonlinear regime

“…Similar to the CD situation here we encounter that in the course of backscattering of electrons in the drive wire the phonons with quasimomentum hq z = 2p n are generated that in their turn are absorbed by the drag wire. The contribution to the current of two subbands ε l + p 2 /2m in the drive wire and ε n +p 2 /2m in the drag wire vanishes unless eV /2 > |ε l − ε n | again similar to the CD case [9]. However, in the phonon drag we encounter the threshold eV /2 > sp n .…”