Research Interests

I have been studying the physis of mesoscopic systems, nano-materials, such as carbon nanotubes, quantum dots, nano-mechanics.

Main studies

Carbon nanotubes:

     Tomonaga-Luttinger liquid:

New J. Phys. 7, 244 (2005). (Tomonaga-Luttinger liquid and NEMS)

     Curvature-induced effects:

J. Phys. Soc. Jpn. 78, 074707 (2009). (Spin-orbit interaction)

SO Dirac Cone
Dirac cone splitting by the spin-orbit interaction

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

     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, Bulk-edge correspondence for edge states. Link to Brief summary.)

Quantum dot:

     Kondo effect:

J. Phys. Soc. Jpn. 74, 103, (2005). (Kondo effect: Review of our research with NRG)

     Spin blockade:

Phys. Rev. Lett. 110, 016803, (2013), Phys. Rev. B, 89, 085302 (2014).
(Amaha, Izumida, et al. Observation of Triple-Quantum-Dot [PRL(2013)] and Quadruplet Spin Blockade in Double-quantum-dot [PRB (2014)]. Explaining the observations by theory with the Master equation method.

Comparison between Exp. and Theory
Comparison between Exp. and Theory for the spin blockade
(from PRB 89 085302 (2015))


Phys. Rev. B 85, 075313 (2012). (Theoretical study on mechanical vibration of rolling NEMS)

Calculated Vibration for rolled semiconductor
Calculated vibrational mode for rolled semiconductor

Phys. Rev. B, 89, 245304 (2014). (Okamoto, Izumida, Friedland, et al. Observation of mechanical vibration of a cylindrical semiconductor. Explaining the observations by theory. Animation of vibration modes is shown as a supplemental material of the paper, here.)


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 Alumni Association, Tohoku University Department of Physics, for the following three papers)
       J. Phys. Soc. Jpn. 78, 074707 (2009)
       Phys. Rev. B 85, 165430 (2012)
       Phys. Rev. B 91, 235442 (2015)



Reprint requirement

If you need reprints of our paper, please contact me by e-mail (, "_at_" ==> "@" ). I will send pdf files.