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Jun Goryo

Publications and source records attributed to Jun Goryo.

28 records · Page 2Linked to original sources
arXiv2008

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).

cond-mat.supr-con↗
arXiv2007

Transient Oscillation of Currents in Quantum Hall Effect of Bloch Electrons

We consider the quantum Hall effect of two-dimensional electrons with a periodic potential and study the time dependence of the Hall and longitudinal currents when the electric field is applied abruptly. We find that the currents oscillate in time with very large frequencies because of quantum fluctuation and the oscillations eventually vanish, for their amplitudes decay as 1/t.

cond-mat.mes-hall↗
arXiv2007

Adiabatic Process and Chern Numbers

We study quantum processes with two or more adiabatic parameters. When the parameters are compactified, a derivative of the Hamiltonian gives a first Chern number, hence an integer. This topological formulation is applied to the AC Josephson effect and the spin Hall effect in semiconductors.

cond-mat.mes-hall↗
arXiv2007

Deconfinement of Vortices with Continuously Variable Fractions of the Unit Flux Quanta in Two-Gap Superconductors

We propose a new stage of confiment-decofinment transition, which can be observed in laboratory. In two-gap superconductors (SCs), two kinds of vortex exist and each of them carries a continuously variable fraction of the unit flux quanta Phi_0=h c / 2 e. The confined state of these two is a usual vortex and stable in the low temperature region of the system under a certain magnetic field above H_c1. We see an analogy to quarks in a charged pion. An entropy gain causes two fractional vortices to be deconfined above a certain temperature.

cond-mat.supr-con↗
arXiv2005

Flux flow resistivity in the two-gap superconductivity

We investigate the flux flow state in a two-gap superconductor in which two s-wave gaps with different amplitudes exist on two separate Fermi surfaces. The flux flow resistivity is obtained on the basis of the Bardeen-Stephen relation and the result agrees well with the anomalous field dependence of the flow resistivity recently observed in the two-gap superconductor MgB2. Some typical properties of the vortex in this system are also discussed.

cond-mat.supr-con↗
arXiv2003

A phenomenology for multiple phases in the heavy fermion skutterudite superconductor PrOs4Sb12

The two superconducting phases recently discovered in skutterudite PrOs4Sb12 are discussed by using the phenomenological Ginzburg-Landau theory in the cubic (tetrahedral) crystal symmetry T_h. Building on experimental imput coming from the recent thermal conductivity measurements, the structure of the gap functions for these two phases are considered for the spin singlet pairing case. One of the phases lying in the high temperature and high field region (the A phase) is a strongly "anisotropic s-wave" state and another phase (the B phase) is "anisotropic s"+ i d-wave state. The B phase breaks cubic crystal symmetry and time reversal symmetry spontaneously. The cubic symmetry breaking in B-phase causes anomalous crystal strain and it could be seen in the anisotropy of thermal expansions and isothermal elastic constants. As a signal of the time reversal symmetry breaking, it is expected that an internal spontaneous magnetization should be observed by the MuSR measurement.

cond-mat.supr-con↗
arXiv2002

On Berry Phase in Bloch States

We comment on the relation between Berry phase and quantized Hall conductivities for charge and spin currents in some Bloch states, such as Bloch electrons in the presence of electromagnetic fields and quasiparticles in the vortex states of superfluid $^3$He. One can find out that the arguments presented here are closely related to the spontaneous polarization in crystalline dielectrics and the adiabatic pumping.

cond-mat.supr-con↗
arXiv2002

Berry phase and spin quantum Hall effect in the vortex state of superfluid He3 in two dimensions

We show that the spin quantum Hall effect in the vortex state of two-dimensional rotating superfluid He3 can be described as an adiabatic spin transport of Bloch quasiparticles. We show that the spin Hall conductivity is written by the Berry phase as well as the Chern number. The results have similarity to the adiabatic pumping of Bloch electrons and the spontaneous polarization in crystalline dielectrics.

cond-mat.supr-con↗