Stephen Hayden
| Correspondence Name | Professor Stephen Hayden |
|---|---|
| Telephone Number | +44 (0)117 928 8715 internal 88715 |
| Fax Number | +44 (0)117 9255624 |
| Email Address | Click here for email address |
| Position | Professor of Physics |
| Office Location | G.28 |
A three year fixed term position is available to investigate the relationship between spin fluctuations and the anisotropic electron nematic phases recently discovered in iron-based superconductors and layered ruthenates (Sr3Ru2O7). The project will involve inelastic neutron and x-ray scattering experiments performed at international facilities (e.g. UK, France, Switzerland) together with low temperature transport and magnetic measurements performed in Bristol. Closing date for applications 9:00am 10 Feb 2012. Apply online at www.bris.ac.uk/boris/jobs/feeds/ads?ID=106871. Further details from Prof. Stephen Hayden (s.hayden(at)bris.ac.uk).
Materials whose electronic properties (such as the electrical resistance) become anisotropic at low temperatures without a change of crystal symmetry are currently very topical in condensed matter physics. Such materials have become known as "electronic nematic phases" (ENP's) and include high-temperature (copper-oxide) superconductors and two-dimensional electronic systems (2DES) at high magnetic fields. This project is to investigate electronic nematic behaviour in the recently discovered iron-based superconductors (e.g. Ba(Fe1-xCox)2As2). We will induce electronic nematic behaviour, measure the collective magnetic correlations using neutron and x-ray scattering and use our measurements to understand the electronic properties. The project offers the possibility to work at international facilities in France, Switzerland, the USA and the UK, with complementary measurements in Bristol. There is scope for developing theoretical modelling and data handling software.
A quantum critical point (QCP) is the point where a continuous phase transition (e.g. ferromagnetism) occurs at zero temperature. "Quantum critically" is currently a hot topic because the occurrence a number of interesting phases, such as high-temperature superconductivity, appears to be connected to QCP's. This project concerns the layered ruthenate Sr3Ru2O7 which has a magnetic-field induced QCP (see figure). The unique feature of Sr3Ru2O7 is the occurrence of a new phase with strong electronic anisotropies at the QCP. This phase is not understood, but appears to be due to a new form of electronic order. In this project, we will use neutron scattering to investigate the magnetic excitations and correlations in the new phase. We have some evidence that the electronic order is driven by the magnetic degrees of freedom of the system. The project offers the possibility to work at international neutron scattering facilities in France and the UK, and involves experiments at high magnetic fields (10T) and low temperatures (50 mK) at the facilities and in Bristol.