Temperature-dependent screening of the edge state around antidots in the quantum Hall regime.

The Aharonov-Bohm effect in a small array of antidots with a large aspect ratio is investigated in the quantum Hall regime. The evolution with temperature of the Aharonov-Bohm oscillations in the magnetic field versus gate voltage (B-V_{g}) plane reveals the temperature dependence of the screening. The self-consistently screened potential of the compressible band surrounding an antidot is observed to gain a progressively steeper slope with increasing temperature.

Observation of the Fano-Kondo antiresonance in a quantum wire with a side-coupled quantum dot.

We have observed the Fano-Kondo antiresonance in a quantum wire with a side-coupled quantum dot. In a weak coupling regime, dips due to the Fano effect appeared. As the coupling strength increased, conductance in the regions between the dips decreased alternately.

Observation of "partial coherence" in an Aharonov-Bohm interferometer with a quantum dot.

We report experiments on the interference through spin states of electrons in a quantum dot (QD) embedded in an Aharonov-Bohm (AB) interferometer. We have picked up a spin-pair state, for which the environmental conditions are ideally similar. The AB amplitude is traced in a range of gate voltage that covers the pair.

Tuning of the Fano effect through a quantum dot in an Aharonov-Bohm interferometer.

The Fano effect, which arises from an interference between a localized state and the continuum, reveals a fundamental aspect of quantum mechanics. We have realized a tunable Fano system in a quantum dot (QD) in an Aharonov-Bohm interferometer, which is the first convincing demonstration of this effect in mesoscopic systems. With the aid of the continuum, the localized state inside the QD acquires itinerancy over the system even in the Coulomb blockade.

Composite fermions and bosons: an invitation to electron masquerade in Quantum Hall.

The two-dimensional electron gas formed at the semiconductor heterointerface is a theater for many intriguing plays of physics. The fractional quantum Hall effect (FQHE), which occurs in strong magnetic fields and low temperatures, is the most fascinating of them. The concept of composite fermions and bosons not only is beautiful by itself but also has proved highly successful in providing pictorial interpretation of the phenomena associated with the FQHE.