Spin blockade and coherent dynamics of high-spin states in a three-electron double quantum dot

TL;DR

This paper investigates spin blockade phenomena and coherent dynamics of high-spin states in a three-electron double quantum dot, demonstrating control and detection of quantum interference effects relevant for quantum computing.

Contribution

It reports the first observation of spin blockade in a three-electron DQD near a specific charge transition and demonstrates coherent control via Landau-Zener-Stückelberg interference.

Findings

Observation of spin blockade near (1,2)-(2,1) charge transition

Detection of Landau-Zener-Stückelberg interference between spin states

Insights into coherence of three-spin states for quantum information

Abstract

Asymmetry in a three-electron double quantum dot (DQD) allows spin blockade, when spin-3/2 (quadruplet) states and spin-1/2 (doublet) states have different charge configurations. We have observed this DQD spin blockade near the (1,2)-(2,1) charge transition using a pulsed-gate technique and a charge sensor. We then use this spin blockade to detect Landau-Zener-St\"uckelberg (LZS) interference and coherent oscillations between the spin quadruplet and doublet states. Such studies add to our understandings of coherence and control properties of three-spin states in a double dot, which in turn would benefit the explorations into various qubit encoding schemes in semiconductor nanostructures.