Observation of excited states in a p-type GaAs quantum dot

TL;DR

This study reports the observation of excited states in a p-type GaAs quantum dot, revealing detailed electronic properties and Coulomb blockade phenomena at very low temperatures, advancing understanding of hole-based quantum dots.

Contribution

It presents the first detailed measurement of excited states in a p-type GaAs quantum dot using scanning probe lithography and low-temperature conductance analysis.

Findings

Coulomb blockade oscillations observed

Charging energies up to 2 meV measured

Single-hole excited states resolved

Abstract

A quantum dot fabricated by scanning probe oxidation lithography on a p-type, C-doped GaAs/AlGaAs heterostructure is investigated by low temperature electrical conductance measurements. Clear Coulomb blockade oscillations are observed and analyzed in terms of sequential tunneling through the single-particle levels of the dot at T_hole = 185 mK. The charging energies as large as 2 meV evaluated from Coulomb diamond measurements together with the well resolved single-hole excited state lines in the charge stability diagram indicate that the dot is operated with a small number of confined particles close to the ultimate single-hole regime.