Rin Okuyama

Observation of a Biexciton Wigner Molecule by Fractional Optical Aharonov-Bohm Oscillations in a Single Quantum Ring.

The Aharonov-Bohm effect in ring structures in the presence of electronic correlation and disorder is an open issue. We report novel oscillations of a strongly correlated exciton pair, similar to a Wigner molecule, in a single nanoquantum ring, where the emission energy changes abruptly at the transition magnetic field with a fractional oscillation period compared to that of the exciton, a so-called fractional optical Aharonov-Bohm oscillation. We have also observed modulated optical Aharonov-Bohm oscillations of an electron-hole pair and an anticrossing of the photoluminescence spectrum at the transition magnetic field, which are associated with disorder effects such as localization, built-in electric field, and impurities.

Optical Phonon Lasing in Semiconductor Double Quantum Dots

We propose optical phonon lasing for a double quantum dot (DQD) fabricated in a semiconductor substrate. We show that the DQD is weakly coupled to only two LO phonon modes that act as a natural cavity. The lasing occurs for pumping the DQD via electronic tunneling at rates much higher than the phonon decay rate, whereas an antibunching of phonon emission is observed in the opposite regime of slow tunneling. Both effects disappear with an effective thermalization induced by the Franck–Condon effect in a DQD fabricated in a carbon nanotube with a strong electron–phonon coupling.

Angular momentum and topology in semiconducting single-wall carbon nanotubes

Semiconducting single-wall carbon nanotubes are classified into two types by means of orbital angular momentum of valley state, which is useful to study their low energy electronic properties in finite-length. The classification is given by an integer

Valley coupling in finite-length metallic single-wall carbon nanotubes

d

Optical Aharonov-Bohm effect on Wigner molecules in type-II semiconductor quantum dots

, which is the greatest common divisor of two integers

Superradiance in transport through ensemble of double quantum dots

n

Magnetoluminescence from trion and biexciton in type-II quantum dot

and

Light Controlled Optical Aharonov–Bohm Oscillations in a Single Quantum Ring

m

Topology in single-wall carbon nanotube of zigzag and armchair type

specifying the chirality of nanotubes, by analyzing cutting lines. For the case that

Topological Phase Transition in Metallic Single-Wall Carbon Nanotube

d