Type-IV Superconductivity: Cooper Pairs with Broken Inversion and Time-Reversal Symmetries in Conventional Superconductors
A. G. Lebed
Department of Physics, University of Arizona, 1118 E. 4-th Street, Tucson, AZ 85721, USA
PACS: 74.20.Rp, 74.25.Op, 74.70.-b
Abstract
Vortex phase in a singlet superconductor in the
absence of impurities is shown to be absolutely unstable
with respect to the appearance of a triplet component which
breaks both inversion and time-reversal symmetries of Cooper
pairs.
Symmetry breaking paramagnetic effects are demonstrated
to be of the order of unity if the orbital upper critical field, Hc2(0),
is of the order of Clogston paramagnetic limiting field,
Hp.
We suggest a generic phase diagram of such type-IV
superconductor, which is singlet one at H=0 and characterized
by mixed singlet-triplet order parameter with broken time-reversal
symmetry in vortex
phase.
A possibility to observe type-IV superconductivity in clean
organic, high-Tc, MgB2, and other superconductors
is discussed.