A two-atom electron pump

TL;DR

This paper demonstrates electron pumping through two phosphorus donors in silicon nanowires, revealing quantized transfer at low frequencies and complex non-adiabatic behavior at higher frequencies, modeled by Landau-Zener transitions.

Contribution

It introduces a novel two-atom electron pump using phosphorus donors in silicon, advancing control over single-electron transfer in nanoelectronics.

Findings

Quantized electron pumping achieved at low frequency.

Distinct non-adiabatic features observed at higher frequencies.

Landau-Zener model successfully reproduces experimental signatures.

Abstract

The fabrication of single atom transistors paved the way for electronics based on single dopants. Recently the spectrum of a single dopant was measured electrically by coupling two such devices. The next step towards promising functionalities for future nanoelectronics consists in manipulating a single electron over two dopants. Here we demonstrate electron pumping through two phosphorus donors in series implanted in a silicon nanowire. While quantized pumping is achieved in the low frequency adiabatic regime, we observe remarkable features at higher frequency when the charge transfer is limited by the different tunneling rates. The transitions between quantum states are modeled involving a Landau-Zener transition, allowing to reproduce in detail the characteristic signatures observed in the non-adiabatic regime.