Ken-Ichiro Imura

Weak (anti-)localization in doped Z_2-topological insulator (2009)

Imura, Ken-Ichiro, Kuramoto, Yoshio, Nomura, Kentaro

Localization properties of the doped Z_2-topological insulator are studied by weak localization theory. The disordered Kane-Mele model for graphene is taken as a prototype, and analyzed with...

Superconductivity and Current Confinement in Z_2 Topological Insulators (2009)

Goryo, Jun, Maeda, Nobuki, Imura, Ken-Ichiro

It is shown that the electric supercurrent flows in a Z_2 topological insulator with U_em(1) X U_z(1) (electromagnetic and spin) gauge symmetries. When U_z(1) is broken, a dissipationless electric...

Anti-localization of graphene under substrate electric field (2009)

Imura, Ken-Ichiro, Kuramoto, Yoshio, Nomura, Kentaro

A simple criterion is provided how the (anti-)localization properties of graphene are determined in the presence of inter-valley scattering, Kane-Mele topological mass term, and Rashba spin-orbit...

Quantum Hall effect in bilayer and multilayer graphenes with finite gate voltage (2008)

Nakamura, Masaaki, Hirasawa, Lila, Imura, Ken-Ichiro

We discuss the quantum Hall effect of bilayer graphene with finite gate voltage where the Fermi energy exceeds the interlayer hopping energy. We calculated magnetic susceptibility, diagonal and...

Colossal spin fluctuations in a molecular quantum dot magnet with ferromagnetic electrodes (2008)

Jonckheere, Thibaut, Imura, Ken-Ichiro, Martin, Thierry

We study electronic transport through a magnetic molecule with an intrinsic spin $S$ coupled to two magnetic electrodes, in the incoherent regime. The molecule is modeled as a single resonant level...

Colossal spin fluctuations in a molecular quantum dot magnet with ferromagnetic electrodes (2008)

Jonckheere, Thibaut, Imura, Ken-Ichiro, Martin, Thierry

We study electronic transport through a magnetic molecule with an intrinsic spin $S$ coupled to two magnetic electrodes, in the incoherent regime. The molecule is modeled as a single resonant level...

Colossal spin fluctuations in a molecular quantum dot magnet with ferromagnetic electrodes (2008)

Jonckheere, Thibaut, Imura, Ken-Ichiro, Martin, Thierry

We study electronic transport through a magnetic molecule with an intrinsic spin $S$ coupled to two magnetic electrodes, in the incoherent regime. The molecule is modeled as a single resonant level...

Numerical study of transport through a single impurity in a spinful Tomonaga-Luttinger liquid (2007)

Hamamoto, Yuji, Imura, Ken-Ichiro, Kato, Takeo

The single impurity problem in a spinful Tomonaga-Luttinger liquid is studied numerically using path-integral Monte Carlo methods. The advantage of our approach is that the system allows for...

Characterization of two-dimensional fermionic insulating states (2007)

Shindou, Ryuichi, Imura, Ken-Ichiro, Ogata, Masao

Inspired by the duality picture between superconductivity and insulator in two spatial dimension, we conjecture that the order parameter, suitable for characterizing 2D fermionic insulating state, is...

Full counting statistics for transport through a molecular quantum dot magnet (2006)

Imura, Ken-Ichiro, Utsumi, Yasuhiro, Martin, Thierry

Full counting statistics (FCS) for the transport through a molecular quantum dot magnet is studied theoretically in the incoherent tunneling regime. We consider a model describing a single-level...

Full counting statistics for transport through a molecular quantum dot magnet (2006)

Imura, Ken-Ichiro, Utsumi, Yasuhiro, Martin, Thierry

Full counting statistics (FCS) for the transport through a molecular quantum dot magnet is studied theoretically in the incoherent tunneling regime. We consider a model describing a single-level...

Plateau transitions in fractional quantum Hall liquids (2004)

Imura, Ken-Ichiro

Effects of backward scattering between fractional quantum Hall (FQH) edge modes are studied. Based on the edge-state picture for hierarchical FQH liquids, we discuss the possibility of the...

Noncommutative geometry and nonabelian Berry phase in the wave-packet dynamics of Bloch electrons (2004)

Shindou, Ryuichi, Imura, Ken-Ichiro

Motivated by a recent proposal on the possibility of observing a monopole in the band structure, and by an increasing interest on the role of Berry phase in spintronics, we studied the adiabatic...

Discrete thermodynamic Bethe ansatz (2004)

Bergere, Michel, Imura, Ken-Ichiro, Ouvry, Stéphane

We propose discrete TBA equations for models with discrete spectrum. We illustrate our construction on the Calogero-Moser model and determine the discrete 2-body TBA function which yields the exact...

Discrete Thermodynamic Bethe Ansatz (2001)

Bergere, Michel, Imura, Ken-Ichiro, Ouvry, Stephane

We propose discrete TBA equations for models with discrete spectrum. We illustrate our construction on the Calogero-Moser model and determine the discrete 2-body TBA function which yields the exact...

Discrete thermodynamic Bethe ansatz (2001)

Bergere, Michel, Imura, Ken-Ichiro, Ouvry, Stéphane

We propose discrete TBA equations for models with discrete spectrum. We illustrate our construction on the Calogero-Moser model and determine the discrete 2-body TBA function which yields the exact...

Discrete thermodynamic Bethe ansatz (2001)

Bergere, Michel, Imura, Ken-Ichiro, Ouvry, Stéphane

We propose discrete TBA equations for models with discrete spectrum. We illustrate our construction on the Calogero-Moser model and determine the discrete 2-body TBA function which yields the exact...

Plateau transitions in fractional quantum Hall liquids (2000)

Imura, Ken-Ichiro

Effects of backward scattering between fractional quantum Hall (FQH) edge modes are studied. Based on the edge-state picture for hierarchical FQH liquids, we discuss the possibility of the...

Plateau transitions in fractional quantum Hall liquids (2000)

Imura, Ken-Ichiro

Effects of backward scattering between fractional quantum Hall (FQH) edge modes are studied. Based on the edge-state picture for hierarchical FQH liquids, we discuss the possibility of the...

Plateau transitions in fractional quantum Hall liquids (1999)

Imura, Ken-Ichiro

Effects of backward scattering between fractional quantum Hall (FQH) edge modes are studied. Based on the edge-state picture for hierarchical FQH liquids, we discuss the possibility of the...

Tunneling into fractional quantum Hall liquids (1998)

Imura, Ken-ichiro

Motivated by the recent experiment by Grayson et.al., we investigate a non-ohmic current-voltage characteristics for the tunneling into fractional quantum Hall liquids. We give a possible explanation...

Tunneling in Paired Fractional Quantum Hall States: Conductance and Andreev Reflection of Non-Abelions (1998)

Imura, Ken-ichiro, Ino, Kazusumi

We study the edge transport properties of paired fractional quantum Hall (FQH) states--- the Haldane-Rezayi (HR), Moore-Read (Pfaffian) and Halperin (331) states. A table of exponents is given for...

Quantum transport in $\nu=2/3$ spin-singlet quantum Hall edges (1997)

Imura, Ken-ichiro, Nagaosa, Naoto

Tunneling conductance $G(T)$ through a constricted point contact is studied for the $\nu=2/3$ spin-singlet edges. Including spin-flip tunneling, Zeeman splitting and random magnetic impurities, we...

Effects of long-range Coulomb interaction on the quantum transport in fractional quantum Hall edges (1997)

Imura, Ken-ichiro, Nagaosa, Naoto

We study the effects of long-range Coulomb interaction (LRCI) on the quantum transport in FQH edges with $\nu=1/(2k+1)$. We consider two models, i.e., the quasi-particle tunneling (QPT) model and the...