Latched Detection of Excited States in an Isolated Double Quantum Dot

TL;DR

This paper demonstrates a method for excited state spectroscopy of an isolated double quantum dot using pulsed gating and capacitive sensing, including a novel latched detection technique for single tunneling events.

Contribution

It introduces a new latched detection method enabling measurement of single tunneling events in an isolated quantum dot system without electrical contact.

Findings

Spectral features revealed by tunneling probabilities.

Latched detection allows single-event measurement.

Excited states characterized without electrical contact.

Abstract

Pulsed electrostatic gating combined with capacitive charge sensing is used to perform excited state spectroscopy of an electrically isolated double-quantum-dot system. The tunneling rate of a single charge moving between the two dots is affected by the alignment of quantized energy levels; measured tunneling probabilities thereby reveal spectral features. Two pulse sequences are investigated, one of which, termed latched detection, allows measurement of a single tunneling event without repetition. Both provide excited-state spectroscopy without electrical contact to the double-dot system.