Physics Colloquium 

The ‘Mott’ metal insulator transition: Is it real, and does it occur in real materials?

Andrew Millis
Professor
Department of Physics
Columbia University

Co-Director
Center for Computational Quantum Physics
Flatiron Institute
New York, NY

Abstract:

The `Mott’ or correlation-driven metal-insulator transition is a basic unifying concept in modern-day condensed matter physics, but its relevance to actual quantum materials has been intensely controversial for decades. After a brief description of the phenomenon and its history, this talk will show how new experiments and new theory are transforming our view of the Mott phenomenon. Theoretical and computational developments, in particular the systematic comparison of results obtained by different methods, establish confidence in our ability to compute crucial aspects of the quantum many-body physics, while new experimental systems and classes of experiments have provided concrete instantiations of the phenomenon, permitting sharp theoretical comparisons. I will argue that recent experiments on Moire materials have unambiguously established the existence of the Mott phase with properties in semiquantitative agreement with theory, while new theoretical developments have demonstrated that in many of the classic transition metal oxide materials, the lattice plays a key role in the transition. The community’s rapidly growing ability to make quantitative theory-experiment comparisons is changing our understanding of quantum materials.

Background:

Andrew Millis is co-director of the Center for Computational Quantum Physics at the Flatiron Institute and professor of physics at Columbia University. He received his Ph.D. in physics from the Massachusetts Institute of Technology in 1986. After that, he worked for 10 years in the theoretical physics research department at Bell Laboratories and then served on the faculty at Johns Hopkins University and Rutgers University before moving to Columbia University in 2001. He served as chair of the Columbia University physics department from 2006 to 2009. He began his association with the Simons Foundation in 2011, serving as associate director for physics in the Mathematics and Physical Sciences division before moving to the Flatiron Institute in the fall of 2017.

Millis’ research interests focus on the theoretical physics of electrons in materials, with a particular focus on collective properties such as superconductivity and magnetism. His recent work has emphasized the development and use of new numerical methods for the many-electron problem and the application of these methods to elucidate the behavior of high-temperature superconductors, oxide superlattices and materials under non-equilibrium conditions.

He is the author of more than 400 papers, is a member of the National Academy of Sciences and is a Fellow of the American Physical Society and of the American Association for the Advancement of Science. He is a member of the Advisory Committee to the Mathematics and Physical Sciences Division of the National Science Foundation and of the advisory board of the U.S. Summer School on Condensed Matter and Materials Physics (which he helped found). He received the 2017 Hamburg Prize for Theoretical Physics, and two of his recent postdoctoral fellows have received IUPAP Young Scientist awards.