Quantum wires coupled by tunneling

The electron tunneling between two quantum wires at a point contact is calculated. Several subbands and a finite tunneling amplitude are considered, while the Coulomb interaction between electrons is neglected. The salient feature is the hybridization-split lower band edge states, which have a large spectral weight because of the diverging one-dimensional Van Hove singularities. For the lowest subband, the bonding state lies below the continuum of states arising from the motion of carriers along the conductors, while the antibonding state is embedded into the continuum and hence has a broadened Structure. A slight disorder could lead to localized states close to the band edges, which would reduce this broadening and thus render the peak observable. (C) 2008 Elsevier B.V. All rights reserved.