Coherent Spin Preparation of Indium Donor Qubits in Single ZnO Nanowires

TL;DR

This paper demonstrates that indium donors in isolated ZnO nanowires retain favorable optical and spin properties, enabling coherent spin preparation crucial for quantum technologies.

Contribution

It shows that indium donor spins in ZnO nanowires can be coherently prepared, maintaining properties similar to bulk material, advancing quantum information applications.

Findings

Optical linewidth of 60 GHz in nanowires close to bulk values

Successful optical spin initialization and coherent population trapping

Two-photon absorption limited by hyperfine interaction

Abstract

Shallow donors in ZnO are promising candidates for photon-mediated quantum technologies. Utilizing the indium donor, we show that favorable donor-bound exciton optical and electron spin properties are retained in isolated ZnO nanowires. The inhomogeneous optical linewidth of single nanowires (60 GHz) is within a factor of 2 of bulk single-crystalline ZnO. Spin initialization via optical pumping is demonstrated and coherent population trapping is observed. The two-photon absorption width approaches the theoretical limit expected due to the hyperfine interaction between the indium nuclear spin and the donor-bound electron.