105 research outputs found
Chiral Correction to the Spin Fluctuation Feedback in two-dimensional p-wave Superconductors
We consider the stability of the superconducting phase for spin-triplet
p-wave pairing in a quasi-two-dimensional system. We show that in the absence
of spin-orbit coupling there is a chiral contribution to spin fluctuation
feedback which is related to spin quantum Hall effect in a chiral
superconducting phase. We show that this mechanism supports the stability of a
chiral p-wave state.Comment: 8 pages. The final version is accepted for publication in Europhys
Let
Topological Origin of Zero-Energy Edge States in Particle-Hole Symmetric Systems
A criterion to determine the existence of zero-energy edge states is
discussed for a class of particle-hole symmetric Hamiltonians. A ``loop'' in a
parameter space is assigned for each one-dimensional bulk Hamiltonian, and its
topological properties, combined with the chiral symmetry, play an essential
role. It provides a unified framework to discuss zero-energy edge modes for
several systems such as fully gapped superconductors, two-dimensional d-wave
superconductors, and graphite ribbons. A variants of the Peierls instability
caused by the presence of edges is also discussed.Comment: Completely rewritten. Discussions on coexistence of is- or
id_{xy}-wave order parameter near edges in d_{x^{2}-y^{2}}-wave
superconductors are added; 4 pages, 3 figure
Quantized spin Hall effect in Helium three-A and other p-wave paired Fermi systems
In this paper we propose the quantized spin Hall effect (SHE) in the vortex
state of a rotating p-wave paired Fermi system in an inhomogeneous magnetic
field and in a weak periodic potential. It is the three dimensional extension
of the spin Hall effect for a 3He-A superfluid film studied in Ref. [1]. It may
also be considered as a generalization of the 3D quantized charge Hall effect
of Bloch electrons in Ref. [2] to the spin transport. The A-phase of 3He or,
more generally, the p-wave paired phase of a cold Fermi atomic gas, under
suitable conditions should be a good candidate to observe the SHE, because the
system has a conserved spin current (with no spin-orbit couplings).Comment: 6 pages, revised version
Spontaneous magnetization and Hall effect in superconductors with broken time-reversal symmetry
Broken time reversal symmetry (BTRS) in d wave superconductors is studied and
is shown to yield current carrying surface states. The corresponding
spontaneous magnetization is temperature independent near the critical
temperature Tc for weak BTRS, in accord with recent data. For strong BTRS and
thin films we expect a temperature dependent spontaneous magnetization with a
paramagnetic anomaly near Tc. The Hall conductance is found to vanish at zero
wavevector q and finite frequency w, however at finite q,w it has an unusual
structure.Comment: 7 pages, 1 eps figure, Europhysics Letters (in press
Vortex with Fractional Quantum Numbers in Chiral p-Wave Superconductor
We show that a vortex in a chiral p-wave superconductor, which has the p_{x}+
i p_{y}-wave pairing state and breaks U(1), parity and time reversal symmetry
simultaneously, has fractional charge -{n e}/{4} and fractional angular
momentum -n^{2}/{16} (n; vorticity). This suggests that the vortex could be
anyon and could obey fractional statistics. Electromagnetic property of the
vortex is also discussed and we find that an electric field is induced near the
vortex core.Comment: 10 pages, 3 figures, accepted for publication in Phys. Rev.
Numerical Renormalization Group Study of Kondo Effect in Unconventional Superconductors
Orbital degrees of freedom of a Cooper pair play an important role in the
unconventional superconductivity. To elucidate the orbital effect in the Kondo
problem, we investigated a single magnetic impurity coupled to Cooper pairs
with a () symmetry using the numerical
renormalization group method. It is found that the ground state is always a
spin doublet. The analytical solution for the strong coupling limit explicitly
shows that the orbital dynamics of the Cooper pair generates the spin 1/2 of
the ground state.Comment: 4 pages, 2 figures, JPSJ.sty, to be published in J. Phys. Soc. Jpn.
70 (2001) No. 1
Axial Anomaly Effect in Chiral p-wave Superconductor
We analyze the chiral p-wave superconductor in the low temperature region.
The superconductor has a epsilon_{x} p_{x} + i epsilon_{y} p_{y}-wave gap in
two dimensional space (2D). Near the second superconducting transition point,
the system could be described by a quasi-1D chiral p-wave model in 2D. The
axial anomaly occurs in such a model and causes an accumulation of the
quasiparticle in an inhomogeneous magnetic field. The effect is related to the
winding number of the gap.Comment: 12 pages, 1 figure, RevTex. The final version is accepted for
publication in J. Phys. Soc. Jp
Impurity Induced Polar Kerr Effect in A Chiral p-wave Superconductor
We discuss the polar Kerr effect (PKE) in a chiral p-wave (p_x+i p_y-wave)
superconductor. It is found that the off-diagonal component of a
current-current correlation function is induced by impurity scattering in the
chiral p-wave condensate, and a nonzero Hall conductivity is obtained using the
Kubo formula. We estimate the Kerr rotation angle by using this
impurity-induced Hall conductivity and compare it with experimental results
[Jing Xia et al., Phys. Rev. Lett. 97, 167002 (2006)].Comment: 4 pages, 2 figures, accepted for publication in Phys. Rev. B Rapid
Communicatio
Temporal Oscillation of Conductances in Quantum Hall Effect of Bloch Electrons
We study a nonadiabatic effect on the conductances in the quantum Hall effect
of two-dimensional electrons with a periodic potential. We found that the Hall
and longitudinal conductances oscillate in time with a very large frequencies
due to quantum fluctuation.Comment: 8 pages, 4 figure
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