News

Paper on magnetotransport studies on FeSe published in PRL

FeSe magnetotransport

Our paper on the magnetotransport behaviour of FeSe was published in Phys. Rev. Lett. 115, 027006 (2015). A previous version of the paper is available on arXiv. By measuring different components of the magnetoresitivity tensor both at very low temperatures using ultra-high magnetic fields up to 90 T and at high temperatures using fields up to 14 T we were able to disentangle to origin of different electronic bands in FeSe.

Paper on the emergence of the nematic phase in FeSe published in PRB as an Editors' Suggestion

Our paper on the emergence of the nematic phase in FeSe has been published in Phys. Rev. B 91, 155106 (2015) . A previous version of the paper is available on arXiv. We present a comprehensive study of the evolution of the nematic electronic structure of FeSe using high resolution angle-resolved photoemission spectroscopy (ARPES), quantum oscillations in the normal state and elastoresistance measurements. We visualize directly the Fermi surface deformation from four-fold to two-fold symmetry across the structural transition.

Paper on Cd3As2 published in PRL as an Editors' Suggestion

Linear Magnetoresistance Caused by Mobility Fluctuations in n-Doped Cd3As2
Cd3As2
Our work on the Dirac semi-metal, Cd3As2, reveal that its linear magnetoresistance is likely to be caused by disorder that occurs in this system as a result of mobility fluctuations. The paper has appeared in Phys. Rev. Lett. 114, 117201 (2015) and a previous version is available on arxiv.

Paper on IrTe2 published in PRB as a Rapid Communication

Fermi surface of IrTe2 in the valence-bond state as determined by quantum oscillations

Our quantum oscillations data has provided evidence that the low temperature Fermi surface of IrTe2 is tilted away from the high temperature structure due to the formation of planes of Ir and Te dimers that cut diagonally through the lattice planes. The paper has been published in Phys. Rev. B 91, 121105(R) (2015) and a previous version is available on the arXiv.

Paper on AgNiO2 published in PRB as a Rapid Communication

Cascade of field-induced magnetic transitions in a frustrated antiferromagnetic metal

Our work on micron-size single crystals of the triangular-lattice metallic antiferromagnet 2H−AgNiO2, in magnetic fields of up to 90 T and temperatures down to 0.35 K show a cascade of magnetic phase transitions. By comparing the experiment with theory we suggest that AgNiO2 may display signature of a supersolid phase in applied magnetic field. The paper was publised in Phys. Rev. B 90, 020401(R) (2014) and a previous version is available on arXiv.

Paper on Ca10(Pt3As8)((Fe1−xPtx)2As2)5 published in PRB

Field-induced magnetic transitions in Ca10(Pt3As8)((Fe1−xPtx)2As2)5 compounds

In this work on Ca10(Pt3As8)((Fe1−xPtx)2As2)5 we find a prominent anomaly in magnetic torque similar to a spin-flop-like transition when the magnetic field is applied perpendicular to the conducting planes, which suggest that is driven by antiferromagnetic fluctuations of magnetic moments aligned preferentially out of the conducting planes at low temperatures. The work was published in Phys. Rev. B 89, 205136 (2014) and a previous version is available on arXiv.

Paper on LiFeAs published in PRL

de Haas–van Alphen Study of the Fermi Surfaces of Superconducting LiFeP and LiFeAs

Quantum oscillations in LiFeAs

This work reports quantum oscillations observed for the first time in the superconducting LiFeAs and LiFeP, two contrasting iron-based superconductors having different gap symmetry and superconducting transition temperatures. The work is in collaboration with the Correlated Electron Group at Bristol University, Kyoto University and measurements were performed at the high magnetic field facilities in Nijmegen and Toulouse. This work was published in Phys. Rev. Lett. 108, 047002 (2012) and a previous version is available on arXiv.

Prizes

MPhys project prizes 2014

Congratulations to Joseph Prentice, University College for the Metaswitch Prize for the best use of Software in a MPhys Project. Joe's project was entitled Mapping Fermi surfaces in materials with hexagonal lattices (supervised by Dr Amalia Coldea).

Congratulations to Nathaniel Davies, Lincoln College for an Physics prize for the best Condensed Matter Physics MPhys Project. Nat's project was entitled The effect of strain on the electronic structure of novel superconducting materials (supervised by Dr Amalia Coldea).

MPhys project prize 2013

Congratulations to James Edmands (Jesus College) for the Gibbs Prize for the best use of experimental apparatus in a MPhys Project (supervised by Dr Amalia Coldea).

MPhys project prizes 2012

Congratulations to Jonasz Slomka, Mansfield College for the Gibbs Prize for the best use of experimental apparatus in a MPhys Project. Jonasz' project was entitled Heat transfer in a nanocalorimeter (supervised by Dr Amalia Coldea).

Congratulations to Samuel Blake, The Queen’s College for the Metaswitch Prize for the best use of Software in a MPhys Project. Sam's project was entitled Electronic structure of novel superconducting materials (supervised by Dr Amalia Coldea).

Euromagnet prize 2011 for Amalia Coldea for research on iron-based superconductors using high magnetic fields

EuroMagnet prize 2011

Amalia Coldea from the Quantum Materials group has been awarded the EuroMagnet prize 2011 for her outstanding contribution to the understanding of the electronic structure of iron-based superconductors by using high magnetic fields. The prize was awarded at the EuroMagnet II User Meeting in Toulouse where Amalia presented her latest research on iron-based superconductors. High magnetic fields and low temperatures are extreme experimental conditions in which one can obtain unique insight into the normal state of superconductors. Under such conditions quantum properties can be directly revealed using highly sensitive experimental tools, such as AFM microcantilevers in micron size single crystals. Quantum oscillations determined by the Landau quantization of the energy levels in magnetic fields provide direct information about the topology of the Fermi surface and about the effect of electronic correlations, which are essential ingredients to build up models for understanding superconductivity and design new materials.