EPSRC PhD in Physics and Astronomy: Quantum optics of giant rydberg excitons in cuprous oxide

Cardiff University
September 01 2017
Position Type
Full Time
Organization Type
Cuprous oxide (Cu2O) is one the oldest, and yet least well-known, semiconductor material.


has a slightly larger band gap than silicon, which means that the

single crystal form of the material is slightly transparent in the

visible part of the spectrum. Cuprous oxide exists in nature and

beautiful deep-red gemstones have been cut and polished from natural

single crystal material. There has been renewed recent interest in

cuprous oxide as a technological material because of potential

applications in photocatalysis and solar energy harvesting.


oxide has an additional extraordinary optoelectronic property. In most

semiconductors, photons with energy just larger than the band gap can

produce bound electron-hole states known has excitons.


excitons are not unlike hydrogen atoms trapped in the solid-state: they

consist of an electron orbiting a positive core (hole).


hydrogen, the excitons also have excited states, which typically take

the form of Rydberg series, and at cryogenic temperatures it is usually

possible to observe a small number (three or four) excited states. Due

to the unusual nature of the Fermi surface in cuprous oxide, however,

very high principal quantum number excitons states can exist.


recent Nature paper reported Rydberg series extending up to n = 25. This

means that the exciton in cuprous oxide is an extraordinarily stable

quantum object, and one that can be readily manipulated with light.


student will be trained in the use of a range of advanced spectroscopic

characterisation tools, including ultrafast lasers, time-resolved

transient FT-IR, and the latest cryogenic techniques.





This project will be supervised by Dr Stephen Lynch and Professor Wolfgang Langbein.

This job comes from a partnership with Science Magazine and Euraxess