According to theory and confirmed by experiment, no metallic phase was thought to be possible in two dimensions. It was therefore a big surprise when an apparent metal-insulator transition was reported in 1994 in the strongly interacting 2D electron system in high mobility silicon MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) [1]. A great deal of theoretical and experimental activity ensued to determine whether this is a transition rather than crossover behavior, and to determine the nature of the transition. Most (but not all) experiments (including our own) have claimed to show that this is a quantum phase transition that occurs at a finite electron density nc in the limit T⟶0. In this talk, I will present new data that holds yet another surprise [2].
[1] S. V. Kravchenko, G. V. Kravchenko, J. E. Furneaux, V. M. Pudalov, and M. D’Iorio, Phys. Rev. B 50, 8039 (1994).
[2] Shiqi Li, Qing Zhang, Pouyan Ghaemi and M. P. Sarachik, Phys. Rev. B 99, 155302 (2019).
Professor Sarachik has been active in defending the human rights of scientists as a National Board member of the Committee of Concerned Scientists, a long-time member of the Human Rights of Scientists Committee of the New York Academy of Sciences, and as a member and chair of the Committee on the International Freedom of Scientists of the American Physical Society.
More information on Professor Sarachik can be found here.