The group explore and investigate novel electronic states, which form near pressure induced quantum phase transitions, where known ordered states such as magnetic, structural, orbital or charge density wave order are frequently replaced by more exotic low temperature states. We have recently mapped out the high pressure phase diagrams of the bilayer ruthenate Ca3Ru2O7, the quasi-skutterudite system (Ca/Sr)3Ir4Sn13, a number of iron-arsenide superconductors, and the cerium based ferrromagnets CeSb2 and CeAgSb2. We have also introduced useful innovations in high pressure techniques, which significantly improve the reliability of our high pressure setups and thereby facilitate more challenging and complex measurements.

These innovations enable us to investigate the Fermi surface, one of the most fundamental properties of a metal, on either side of a pressure induced quantum phase transition. Fermi surface sensitive probes are to electronic structure determination what x-ray diffraction is to atomic structure determination, and they have played a key role in developing our understanding of electrons in solids. When the Fermi surface can be detected experimentally, such measurements have the power to decide scientific debates. We are now set to exploit this capability in high pressure Fermi surface measurements on (i) Mott insulators metallised by high pressure, such as NiS2 and Ca2RuO4, (ii) metals with spin density wave order, such as Cr, (iii) ferromagnetic heavy fermion materials such as CeSb2 and CeAgSb2. This work will be complemented by high pressure lattice structure determination by x-ray diffraction at the new Diamond Light Source synchrotron facility.

Condensed matter research explores the boundless materials frontier. High quality crystals of new materials are the lifeblood of our research: they are required for building our understanding of so far unexplained phenomena, and they frequently give rise to unexpected discoveries. The Quantum Matter group has a history of growing high purity crystals, which have been instrumental in some of our best work. Modern crystal growth infrastructure is provided in the recently refurbished material preparation laboratory, which is set to play an increasingly important part in future projects.

We run a laboratory for high pressure, low temperature research on correlated electron materials. The laboratory includes a low temperature SQUID magnetometer, a general purpose low temperature physical properties measurement system, and a specialised low temperature and high magnetic field system, which can cool to 0.1 K above absolute zero without using liquefied helium. It also includes facilities for crystal growth, including two box furnaces, a glass-blowing facility to close quartz ampoules, two radio-frequency induction furnaces and an infrared mirror furnace.