We work across the chemistry-physics boundary with a focus on structure-property relationships in advanced functional materials and quantum phases (with the former including ferroelectrics and multiferroics and the latter materials whose properties are driven by quintessentially quantum phenomena such as quantum spin liquids and unconventional superconductors). The core experimental tools we employ include sample synthesis (including substitutional studies order to tune material properties), detailed characterisation measurements, physical property measurements and, last but not least, high resolution neutron diffraction and other facility-based techniques.
Please find below some of our recent work and interests:
Structure and magnetism in iridates
We have pioneered the use of 193Ir, a previously unused isotope of iridium with improved neutron scattering characteristics compared to the natural isotopic mixture. We are now focusing on exploiting this in studies of the structure-property relationships in iridates.
“Neutron scattering length determination by means of total scattering”
Journal of Applied Crystallography 51, 854 (2018)
“Pressure-induced collapse of the spin-orbital Mott state in the hyperhoneycomb iridate β−Li2IrO3“
Physical Review B 99, 125127 (2019)
“Robust spin-orbit coupling induced semimetallic state in hyperkagome iridate Li3Ir3O8“
Physical Review Materials 4, 075002 (2020)
New quantum magnets
Quantum magnets provide an intriguing range of physics to explore, closely linked to structural distortions. We are interested in synthesis, high resolution structural studies and detailed physical property measurements of such materials.
“S=1/2 quantum critical spin ladders produced by orbital ordering in Ba2CuTeO6“
Physical Review B 95, 104428 (2017)
“Spin dynamics of coupled spin ladders near quantum criticality in Ba2CuTeO6“
Physical Review B 98, 174410 (2018)
High resolution neutron diffraction studies of ferroelectrics and multiferroics
Ferroelectrics and multiferroics are both useful for applications in everyday devices and of fundamental interest for the phase transitions and complex physical properties they host. We have a particular interest in studying these materials using high resolution neutron diffraction and symmetry mode analysis to elucidate the structural distortions driving these properties.
“High-temperature phase transitions of hexagonal YMnO3“
Physical Review B 83, 094111 (2011)
“High-temperature phases of multiferroic BiFe0.7Mn0.3O3“,
Physical Review B 87, 224109 (2013)
Itinerant strongly correlated electron systems
These are materials in which strong electron-electron interactions give rise to intriguing, and often surprising, electronic states. Our interest is largely in growth of ultra-pure single crystals by e.g. the floating zone method, combined with physical property measurements at low temperatures (e.g. ac susceptibility, quantum oscillations, resistivity).
“Resistivity in the Vicinity of a van Hove Singularity: Sr2RuO4 under Uniaxial Pressure”
Physical Review Letters 120, 076602 (2018)
“Strong peak in Tc of Sr2RuO4 under uniaxial pressure”
Science 355, eaaf9398 (2017)
“Search for spontaneous edge currents and vortex imaging in Sr2RuO4 mesostructures”
Physical Review B 89, 144504 (2014)
“Strong Increase of Tc of Sr2RuO4 under both Tensile and Compressive Strain”
Science 344, 283 (2014)
Metallic delafossite oxides such as PdCoO2, PdCrO2 and their relatives show incredibly high conductivities and are a playground for investigating the fundamentals of electronic transport in solids. They act as ‘natural heterostructures’ of highly conducting platinum group metal layers and strongly correlated oxide layers. We have investigated the Fermi surfaces and electronic properties of these materials using quantum oscillation measurements at millikelvin temperatures.
Quantum Oscillations and High Carrier Mobility in the Delafossite PdCoO2
Physical Review Letters 109, 116401 (2012)
Quantum oscillations and magnetic reconstruction in the delafossite PdCrO2
Physical Review B 92, 014425 (2015)
Magnetic frustration and spontaneous rotational symmetry breaking in PdCrO2
Physical Review B 100, 094414 (2019)