Lancaster University Centre for Nanoscale Dynamics and Mathematical Modelling

Superconductivity and ferromagnetism are quantum phenomena which induce macroscopic order into the charge and spin degrees of freedom of the mobile electrons in solid state materials. On the mesoscopic scale, these effects spread out into neighbouring components when they are brought into contact with each other. The electronic properties of such devices is governed by the dynamical interplay of quantum effects and displays a rich phenomenology. Hybrid systems can also be formed by using unorthodox materials such as graphene, carbon nanotubes or individual molecules.

Our research addresses the electronic properties of hybrid systems in a multitude of settings, e.g. in Andreev billards involving superconducting leads, spin valves with ferromagnetic components, or layered structures that produce a giant magnetoresistance. This requires to employ a variety of analytical techniques from semiclassics, quasiclassics, diagrammatics and random-matrix theory, and also involves the numerical modelling within first-principle and real-space renormalization approaches. The issues which we address range from fundamental questions in the development and applicability of these techniques to the identification of a robust phenomenology for the functionality of devices in prospective applications.

Illustration of Andreev reflection at the interface of a superconductor and a normal metal.

List of publications

Giant magnetoresistance of nickel-contacted carbon nanotubes Journal of Physics-Condensed Matter 19, 042201 (2007) S. Athanasopoulos, S. W. Bailey, J. Ferrer, V. M. Garcia Suarez, C. J. Lambert, A. R. Rocha, and S. Sanvito
0-pi transition in superconductor-ferromagnet-superconductor junctions with strongly spin-dependent scattering Physical Review B 75, 132502 (2007) O. Kashuba, Y. M. Blanter, and V. I. Fal'ko
Andreev edge channels and magnetic focusing in normal-superconductor systems: A semiclassical analysis Physical Review B 76, 064516 (2007) P. Rakyta, A. Kormanyos, Z. Kaufmann, and J. Cserti
Giant magnetothermopower and magnetoresistance in metals with embedded ferromagnetic nanoclusters Journal of Applied Physics 101, 014324 (2007) O. Tsyplyatyev, O. Kashuba, and V. I. Fal'ko
Quantized invariant tori in Andreev billiards of mixed phase space Physical Review B 73, 214526 (2006) Z. Kaufmann, A. Kormanyos, J. Cserti, and C. J. Lambert
Quantum-classical correspondence in the wave functions of Andreev billiards Physical Review Letters 96, 237002 (2006) A. Kormanyos, Z. Kaufmann, J. Cserti, and C. J. Lambert
Superconducting terminals as sensitive probes for scarred states Physical Review Letters 97, 124102 (2006) A. Kormanyos and H. Schomerus
Andreev drag effect via magnetic quasiparticle focusing in normal-superconductor nanojunctions Physical Review B 74, 132508 (2006) P. K. Polinak, C. J. Lambert, J. Koltai, and J. Cserti
Thermally excited spin current and giant magnetothermopower in metals with embedded ferromagnetic nanoclusters Physical Review B 74, 132403 (2006) O. Tsyplyatyev, O. Kashuba, and V. I. Fal'ko
Bound states in Andreev billiards with soft walls Physical Review B 72, 075304 (2005) F. Libisch, S. Rotter, J. Burgdorfer, A. Kormanyos, and J. Cserti
Ring-shaped Andreev billiards in quantizing magnetic fields Physical Review B 69, 134514 (2004) J. Cserti, P. Polinak, G. Palla, U. Zulicke, and C. J. Lambert
Andreev bound states for a superconducting-ferromagnetic box Physical Review B 69, 092506 (2004) J. Koltai, J. Cserti, and C. J. Lambert
Effective description of the gap fluctuation for chaotic Andreev billiards Physical Review B 70, 052512 (2004) A. Kormanyos, Z. Kaufmann, C. J. Lambert, and J. Cserti
Magnetic field influence on the proximity effect in semiconductor-superconductor hybrid structures and their thermal conductance Physical Review B 69, 092503 (2004) G. Tkachov and V. I. Fal'ko
Logarithmic contribution to the density of states of rectangular Andreev billiards Physical Review B 67, 172506 (2003) A. Kormanyos, Z. Kaufmann, J. Cserti, and C. J. Lambert
Magnon-assisted transport and thermopower in ferromagnet-normal-metal tunnel junctions Physical Review B 68, 172404 (2003) E. McCann and V. I. Fal'ko
Proximity-induced subgaps in Andreev billiards Physical Review Letters 89, 057001 (2002) J. Cserti, A. Kormanyos, Z. Kaufmann, J. Koltai, and C. J. Lambert
Giant magnetothermopower of magnon-assisted transport in ferromagnetic tunnel junctions Physical Review B 66, 134424 (2002) E. McCann and V. I. Fal'ko
Magnetothermopower and magnon-assisted transport in ferromagnetic tunnel junctions Applied Physics Letters 81, 3609 (2002) E. McCann and V. I. Fal'ko
Subgap transport in ferromagnet-superconductor junctions due to magnon-assisted Andreev reflection Physical Review B 65, 024519 (2002) G. Tkachov, E. McCann, and V. I. Fal'ko
Magnon-assisted Andreev reflection in a ferromagnet-superconductor junction Europhysics Letters 56, 583 (2001) E. McCann and V. I. Fal'ko
Large sample-to-sample fluctuations of the nonequilibrium critical current through mesoscopic Josephson junctions Physical Review B 6305, 054512 (2001) P. Samuelsson and H. Schomerus
Spin-polarized transport in F/S nanojunctions Journal of Low Temperature Physics 124, 305 (2001) F. Taddei, S. Sanvito, and C. J. Lambert
Enhancement of giant magnetoresistance due to spin mixing in magnetic multilayers with a superconducting contact Physical Review B 6301, 012404 (2001) F. Taddei, S. Sanvito, and C. J. Lambert
Andreev levels in a single-channel conductor Physical Review B 6413, 134206 (2001) M. Titov, N. A. Mortensen, H. Schomerus, and C. W. J. Beenakker
Excitation spectrum of Andreev billiards with a mixed phase space Physical Review Letters 82, 295 (1999) H. Schomerus and C. W. J. Beenakker