Professor Stephen Blundell

Abstract:

We present a numerical simulation of angle dependent magnetoresistances oscillations(AMROs) in alpha-(BEDT-TTF)(2)KHg(SCN)(4). The nesting vector of the density wave and the magnetic breakdowngap in the low-temperature, low-magnetic-field state (LTLF) are constrained by simulations of quasi-one-dimensional (Q1D) AMRO. Quasi-two-dimensional (Q2D) AMRO simulations for the high-temperature, high-magnetic-field state (HTHF) allow the precise derivation of an ellipticity of the Q2D Fermi surface. Simulations of the field dependent AMRO demonstrate the gradual evolution of the FS from LTLF to HTHF states toward the kink transition at 23 T.

Abstract:

We present a numerical simulation of angle dependent magnetoresistances oscillations (AMROs) in α-(BEDT-TTF)2KHg(SCN)4. The nesting vector of the density wave and the magnetic breakdowngap in the low-temperature, low-magnetic-field state (LTLF) are constrained by simulations of quasi-one-dimensional (Q1D) AMRO. Quasi-two-dimensional (Q2D) AMRO simulations for the high-temperature, high-magnetic-field state (HTHF) allow the precise derivation of an ellipticity of the Q2D Fermi surface. Simulations of the field dependent AMRO demonstrate the gradual evolution of the FS from LTLF to HTHF states toward the kink transition at 23 T.

Abstract:

We have developed a model for parameterizing the shape of the quasi-two-dimensional (Q2D) Fermi surface (FS) sections found in many organic molecular metals. Using this model, we show that it is possible to extract more detail about the Q2D pocket shape from angle-dependent magnetoresistance oscillations than in the traditional approximation which assumes an elliptical FS shape. We also consider the implications for cyclotron resonance experiments.

Abstract:

We have developed a model for parameterizing the shape of the quasi-two-dimensional (Q2D) Fermi surface (FS) sections found in many organic molecular metals. Using this model, we show that it is possible to extract more detail about the Q2D pocket shape from angle-dependent magnetoresistance oscillations than in the traditional approximation which assumes an elliptical FS shape. We also consider the implications for cyclotron resonance experiments.

Abstract:

mu SR has been used to probe the structure and stability of the flux vortex array in the organic superconductor kappa-(BEDT-TTF)(2)Cu(SCN)(2), At temperatures below 5 K and fields below 5 mT the internal field distribution is found to closely match that expected for a three dimensional (3D) Abrikosov flux line lattice (FLL). Careful studies in this 3D-FLL regime have enabled an improved measurement of the temperature dependence of the superconducting penetration depth to be made. A linear term is found in the temperature dependence of the penetration depth, suggesting the presence of line nodes in the gap parameter and d-wave pairing.