2023 Henry Moseley Medal and Prize

Dr Hannah Stern has made advances in the fundamental optoelectronic properties of solid-state systems. Her work focuses on the excited-state dynamics of novel material platforms, in particular the interplay of their optical behaviour and spin physics. Her discoveries have impacted the design of next-generation solar cells and future quantum technologies.

Stern has made key contributions in two fields. First, she advanced the fundamental understanding of the process by which a photogenerated spin singlet exciton can, in certain molecular semiconductors such as tetracene, split to form a pair of spin triplet excitons. She identified an intermediate state, of two adjacent and closely bound triplets, and showed how this can resolve the surprise that this energetically uphill singlet fission process can show no thermal activation. This work underpins current efforts to develop more efficient solar cells that can harvest both triplet excitons in a standard silicon cell.

Second, she has pioneered research on the manipulation of single spin defects in atomically thin hexagonal boron nitride. Her work has led to the first singly addressable zero-field spin qubit in a two-dimensional material at room temperature. This work includes coherent control of a single spin in this material and has generated significant interest because it opens new opportunities for quantum networking and sensing technologies.

Stern’s impactful contributions to different scientific fields are remarkable given her relatively short career to date. In her work, she has demonstrated her flair for interdisciplinary research by merging expertise across physics, materials science and chemistry to reveal elusive photophysical processes. She has been awarded a Royal Society University Research Fellowship (2022) to pursue a two-dimensional spin-photon interface for quantum technologies and is part of the organizing committee for the Engineering and Physical Sciences Research Council’s Materials for Quantum Network.

Prior to her postdoctoral work, Stern won a Junior Research Fellowship from Trinity College Cambridge. Along with her focus on fundamental research, she is motivated to translate research to industry. During her postdoctoral fellowship, she co-founded a spin off company, Hexagonfab, that uses two-dimensional materials for biosensing.

Stern is passionate about encouraging diversity in science and is an outward-looking role model in the Physics Department at the University of Cambridge. As a PhD student, she co-founded Cavendish Inspiring Women, a society that promotes minorities in physics. Now eight years running, Cavendish Inspiring Women continues to support students and postdocs in the department.