Conductance and polarization in quantum junctions

Abstract

We revisit the expression for the conductance of a general nanostructure -- such as a quantum point contact -- as obtained from the linear response theory. We show that the conductance represents the strength of the Drude singularity in the conductivity $\sigma (k,k^{\prime };i\omega \to 0)$. Using the equation of continuity for electric charge we obtain a formula for conductance in terms of polarization of the system. This identification can be used for direct calculation of the conductance for systems of interest even at the {\it ab-initio} level. In particular, we show that one can evaluate the conductance from calculations for a finite system without the need for special ``transport'' boundary conditions.

References in corpus (4)

• The GW method
• Integrability and ideal conductance at finite temperatures
• Landauer Conductance without Two Chemical Potentials
• Electron transport in a quantum wire with realistic Coulomb interaction

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• Ab-initio formulation of the 4-point conductance of interacting electronic systems
• First-Principles conductance of nanoscale junctions from the polarizability of finite systems
• On the role of the nonlocal Hartree-Fock exchange in ab initio quantum transport: Hydrogen in Platinum nanocontacts revisited
• Conductance of Quantum Impurity Models from Quantum Monte Carlo