Research

Research interests | Quantum dots | Carbon nanotubes | Nanomechanics | Awards | Publications and presentations | Requests for papers

Research interests

My research is in theoretical condensed matter physics. My main research areas are mesoscopic physics, spintronics, and nanomechanics, with particular interest in quantum transport, carbon nanotubes, quantum dots, and spin-related phenomena.

My research aims to understand quantum phenomena in nanoscale and mesoscopic systems, particularly the interplay among electronic, spin, geometrical, and mechanical degrees of freedom.

Quantum dots

Kondo effect

J. Phys. Soc. Jpn. 74, 103 (2005) — Review of our studies of the Kondo effect in quantum dots using the numerical renormalization group (NRG).
W. Izumida, "Kondo Effects in Quantum Dots: Theory" , in Encyclopedia of Condensed Matter Physics, 2nd ed., Vol. 3, 381–387 (Elsevier, 2024).

Spin blockade

Phys. Rev. Lett. 110, 016803 (2013) , Phys. Rev. B 89, 085302 (2014) .

Experimental observation and theoretical analysis of spin blockade in triple and double quantum dots. The transport properties are described using master-equation approaches.

Comparison between Exp. and Theory for the spin blockade
（from PRB 89 085302 (2014)）

Carbon nanotubes

Tomonaga-Luttinger liquid

New J. Phys. 7, 244 (2005) — Tomonaga-Luttinger liquid and nanoelectromechanical effects in carbon nanotubes.

Curvature-induced effects

J. Phys. Soc. Jpn. 78, 074707 (2009) — Curvature-induced spin-orbit interaction in single-wall carbon nanotubes.

Dirac cone splitting by the spin-orbit interaction

Phys. Rev. B 85, 165430 (2012) — Linear band tilting and the vernier spectrum.

Phys. Rev. B 111, 045121 (2025) — Group-theoretical analysis of curvature-induced effects.

Finite-length effects (mesoscopic effects)

Phys. Rev. B 91, 235442 (2015) — Valley coupling in finite-length carbon nanotubes.

Phys. Rev. B 93, 195442 (2016) — Angular momentum and valley coupling, and bulk-edge correspondence for edge states. Brief summary .

Topological states

J. Phys. Soc. Jpn. 86, 013702 (2017) — Topological phase transition in metallic single-wall carbon nanotubes.

Phys. Rev. B 96, 125414 (2017) — Topological edge states in carbon nanotubes with superconducting correlations.

Phys. Rev. B 97, 075141 (2018) — Majorana quasiparticles in carbon nanotubes.

Electron correlation

Phys. Rev. Lett. 125, 056401 (2020) — Electron-correlation effects on topological edge states.

Review / book chapter on carbon nanotubes

W. Izumida, "Quantum Effects in Carbon Nanotubes: Effects of Curvature, Finite-Length and Topological Property" , in Quantum Hybrid Electronics and Materials, 123–148 (Springer, 2022).

Nanomechanics

Mechanical vibration of rolled-up semiconductors

Phys. Rev. B 85, 075313 (2012) — Theoretical study of mechanical vibrations of rolled-up semiconductor nanostructures.

Calculated vibrational mode for rolled semiconductor

Phys. Rev. B 89, 245304 (2014) — Experimental observation and theoretical analysis of mechanical vibrations of cylindrical semiconductor structures. Animations of the vibration modes are available here .

Nanorotor driven by electron spin

Phys. Rev. Lett. 128, 017701 (2022) — Proposal for a nanorotor driven by electron-spin injection.

Schematic diagram of a nanomotor driven by spin injection

Awards

2014/03/29: 19th JPS Award for Outstanding Papers (for the following paper)

J. Phys. Soc. Jpn. 78, 074707 (2009)

2015/10/31: 11th Morita-Kinen Prize (from the Alumni Association, Department of Physics, Tohoku University, for the following three papers)

Publications and presentations

Publications

Presentations

Requests for papers

If you would like a PDF copy of any of our papers, please contact me by e-mail (wizumida_at_tohoku.ac.jp, "_at_" ==> "@").