Physics Colloquium

Myriam P. Sarachik

Distinguished Professor Emerita
Physics Department
The City College of New York

The Metal-Insulator Transition (MIT) in two dimensions: Yet Another Surprise.*

Shiqi Li, Qing Zhang, Pouyan Ghaemi and M. P. Sarachik

City College of New York, CUNY

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 in the limit T⟶0 at a finite electron density nc. In this talk, I will present new data that holds yet another surprise [2].

* Work supported by the National Science Foundation grant DMR-1309008 and the

Binational Science Foundation Grant 2012210.

[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).

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Professor Sarachik has been awarded the 2020 APS Medal for Exceptional Achievement in Research.  The medal recognizes contributions of the highest level that advance our knowledge and understanding of the physical universe in all its facets, and is presented along with a $50,000 prize.  The 2020 APS Medal is presented to Sarachik “for fundamental contributions to the physics of electronic transport in solids and molecular magnetism.”

The Low Temperature Research Group at the City College of New York (CCNY) Physics Department is dedicated to the study of condensed matter properties at low temperature. We are currently interested in two areas:

(I) Molecular Nanomagnets
(II) Novel Phenomena in Dilute Two-Dimensional Electron Systems.