Role of Many-particle excitations in Coulomb Blockaded Transport

TL;DR

This paper investigates how electron-electron and electron-phonon interactions influence transport in Coulomb Blockade, revealing complex phenomena like negative differential resistance, hysteresis, and anomalous phonon behavior through direct Fock space analysis.

Contribution

It introduces a direct Fock space approach to analyze nontrivial many-particle excitations affecting Coulomb Blockade transport, highlighting phenomena beyond mean-field approximations.

Findings

Electron-electron interactions cause gateable excitations observable in current-voltage curves.

Separation of excitations into slow traps and fast channels leads to phenomena like negative differential resistance.

Electron-phonon correlations can cause breakdown of expected phonon intensity ratios and anomalous phonon population behavior.

Abstract

We discuss the role of electron-electron and electron-phonon correlations in current flow in the Coulomb Blockade regime, focusing specifically on nontrivial signatures arising from the break-down of mean-field theory. By solving transport equations directly in Fock space, we show that electron-electron interactions manifest as gateable excitations experimentally observed in the current-voltage characteristic. While these excitations might merge into an incoherent sum that allows occasional simplifications, a clear separation of excitations into slow `traps' and fast `channels' can lead to further novelties such as negative differential resistance, hysteresis and random telegraph signals. Analogous novelties for electron-phonon correlation include the breakdown of commonly anticipated Stokes-antiStokes intensities, and an anomalous decrease in phonon population upon heating due to reabsorption of emitted phonons.