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

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


It


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.


Cuprous


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.


These


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


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


Like


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.


A


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.


The


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