Physical Review Letters -- April 26, 1999 -- Volume
82, Issue 17, pp. 3516-3519
Quantum Hall Plateau Transitions in Disordered Superconductors
V. Kagalovsky,1,2 B. Horovitz,1 Y. Avishai,1 and J. T. Chalker3
1 Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva
84105, Israel
2 The Technological College of Beer-Sheva, School of Engineering, Beer-Sheva
84100, Israel
3 Theoretical Physics, Oxford University, Oxford OX1 3NP, United Kingdom
(Received 24 November 1998)
We study a delocalization transition for noninteracting quasiparticles
moving in two dimensions,
which belongs to a new symmetry class. This symmetry class can be realized
in a dirty, gapless
superconductor in which time-reversal symmetry for orbital motion is broken,
but spin-rotation
symmetry is intact. We find a direct transition between two insulating
phases with quantized Hall
conductances of zero and two for the conserved quasiparticles. The energy
of the quasiparticles acts as a relevant symmetry-breaking field at the critical
point, which splits the direct transition into two conventional plateau transitions.
©1999 The American Physical Society
PACS: 73.40.Hm, 71.70.Ej, 72.15.Rn, 74.40.+k