Hideaki Takayanagi

The University of Tokyo

Please join us for two talks by Prof. Hideaki Takayanagi, Executive Director at National Institutes of Natural Sciences, Project Professor at the University of Tokyo.

1. Andreev Reflection and Superconducting Proximity Effect - Past & Present

Andreev reflection is reviewed at the interface between the 2DEG of InAs and Nb. In this talk a superconducting quantum point contact as well as the Fabry–Pérot quantum interferometer are explained. Andreev reflection in the quantum Hall effect regime is also discussed. The superconducting proximity effect is thought to be a mirror effect of Andreev reflection. This

Proximity effect is reviewed from the view point of UCF-like mesoscopic fluctuations of the critical current and long-range phase coherent effect. Both of Andreev reflection and proximity effect have been drawing attention because of the possibility of Majorana Fermions. Recent progress in this field is also introduced.

2. Two-dimensional Organic Semiconductor Crystals

We demonstrate that wafer-size single crystals composed of an organic semiconductor bimolecular layer with an excellent mobility of 10 cm²V⁻¹s⁻¹ can be successfully formed via a simple one-shot solution process. A molecularly flat single crystal of high-mobility organic semiconductors serves as a defect-free interface that facilitates two-dimensional confinement of high-density holes. A remarkably low sheet resistance of 6 kΩ and high hole-gas density of 10¹⁴ cm⁻² result in a metal–insulator transition at ambient pressure. In this talk physical properties of the hole gas are discussed and several device application are also introduced.