Inelastic Cotunneling Resonances in the Coulomb-Blockade Transport in Donor-Atom Transistors

TL;DR

This paper investigates inelastic cotunneling resonances in phosphorus donor transistors, revealing unique excitation-related features in Coulomb blockade transport supported by theoretical modeling.

Contribution

It provides the first detailed experimental observation of inelastic cotunneling resonances in donor-atom transistors, supported by theoretical calculations.

Findings

Observation of resonant-like inelastic cotunneling peaks

Distinct inelastic cotunneling features compared to previous reports

Theoretical support for two-level quantum dot model

Abstract

We report finite-bias characteristics of electrical transport through phosphorus donors in silicon nanoscale transistors, in which we observe inelastic-cotunneling current in the Coulomb blockade region. The cotunneling current appears like a resonant-tunneling current peak emerging from the excited state at the crossover between blockade and non-blockade regions. These cotunneling features are unique, since the inelastic-cotunneling currents have so far been reported either as a broader hump or as a continuous increment of current. This finding is ascribed purely due to excitation-related inelastic cotunneling involving the ground and excited states. Theoretical calculations were performed for a two-level quantum dot, supporting our experimental observation.