Effects of Polaron Formation in Semiconductor Quantum Dots on Transport Properties

TL;DR

This paper theoretically investigates how polaron formation in semiconductor quantum dots influences electron transport, revealing observable Rabi splitting, peak suppression, and interference effects in conductance measurements.

Contribution

It introduces a theoretical framework showing the impact of polaron formation on transport properties, including Rabi splitting and conductance suppression in quantum dots.

Findings

Rabi splitting appears in differential conductance peaks.

Polaron formation suppresses conductance peak height.

A sharp dip in conductance occurs due to destructive interference.

Abstract

We theoretically examine the effects of polaron formation in quantum dots on the transport properties. When a separation between two electron-levels in a quantum dot matches the energy of the longitudinal optical (LO) phonons, the polarons are strongly formed. The Rabi splitting between the levels is observable in a peak structure of the differential conductance G as a function of the bias voltage. The polaron formation suppresses the peak height of G, which is due to the competition between the resonant tunneling (resonance between a level in the dot and states in the leads) and the polaron formation (Rabi oscillation between two levels in the dot). G shows a sharp dip at the midpoint between the split peaks. This is attributable to the destructive interference between bonding and anti-bonding states in a composite system of electrons and phonons.