UNSW Gordon Godfrey Seminars Aug23 2005

Gordon Godfrey Theoretical Seminar 2005

Orbital currents and d-density wave order in strongly correlated electron systems

Dr John Fjaerestad
University of Queensland

Date
Tuesday, 23 August, 2005
School of Physics, 12 pm.,
Room 5

Abstract
Recently it has been suggested that phases with ordered [1,2] or fluctuating [3] orbital currents may be realized in the so-called pseudogap region of the phase diagram of the cuprate superconductors. These proposals have led to much interest in the question of what kinds of models of strongly correlated electrons can give rise to exotic phases of this type. I first give a general introduction to such phases, including how to experimentally detect one of them, known as the staggered flux or d-density wave phase, using neutron scattering. Then I discuss analytical and numerical studies of a generalized Hubbard model on a two-leg ladder at zero temperature [4-7]. These studies show conclusively that this model is in a staggered flux/d-density wave phase in a certain parameter region. Away from half-filling the orbital currents are found to coexist with a charge density wave.

[1] C.M. Varma, Phys. Rev. Lett. 83, 3538 (1999).
[2] S. Chakravarty, R.B. Laughlin, D.K. Morr, and C. Nayak,
Phys. Rev. B 63, 094503 (2001).
[3] P.A. Lee, Physica C 408-410, 5 (2004).
[4] J.O. Fjaerestad and J.B. Marston, Phys. Rev. B 65, 125106 (2002).
[5] J.B. Marston, J.O. Fjaerestad, and A. Sudbo,
Phys. Rev. Lett. 89, 056404 (2002).
[6] U. Schollwöck, S. Chakravarty, J.O. Fjaerestad, J.B. Marston,
and M. Troyer, Phys. Rev. Lett. 90, 186401 (2003).
[7] J.O. Fjaerestad, J.B. Marston and U. Schollwöck, cond-mat/0412709.

Further Information

Contact

Professor Oleg Sushkov