Theory of correlated electron transport and inelastic tunneling spectroscopy

TL;DR

This paper develops a theoretical framework for electron transport and inelastic tunneling spectroscopy in non-superconducting systems, incorporating electron-electron interactions and revealing the role of susceptibilities in tunneling currents.

Contribution

It introduces a comprehensive model that includes correlated tunneling effects and connects tunneling current to susceptibilities, extending beyond traditional single-particle descriptions.

Findings

Tunneling current depends on density of states and susceptibilities.

Correlated tunneling effects are significant in non-superconducting systems.

Experimental signatures of susceptibilities have been observed.

Abstract

For a non-superconducting system, the electronic tunneling current through an insulating barrier is calculated, including interaction effects. The exact Hamiltonian of the full system is projected onto the subspaces of the "left" and "right" leads. In the weak tunneling limit the well-known tunneling Hamiltonian is recovered, along with an additional term. This additional term originates from the projection of the electron-electron interaction onto each subsystem and corresponds to correlated tunneling. It is shown that the tunneling current is determined by---in addition to the single-particle density of states---the spin-spin and density-density susceptibilities. The signatures of which have recently been observed in several experiments.