Bad Metals and Electronic Orders – Nematicity in Iron Pnictides and Moiré Systems

Qimiao Si

Department of Physics and Astronomy, Center for Quantum Materials, Rice University



Strongly correlated electron systems are typically bad metals, which are operationally defined as having a room temperature resistivity that is above the Mott-Ioffe-Regel limit. One of the salient characteristics of these systems is a spectacularly rich landscape of electronic orders. Exploring this landscape is an important means for understanding the underlying microscopic physics.

Iron-based superconductors provide a case study. They show a great variation in the types of electronic orders. In spite of this disparity, it is remarkable that essentially all of these ordered states are accompanied by nematicity. In this talk, I will discuss our efforts in seeking a unified framework, both to understand these electronic orders and to connect them with the microscopic physics of bad metals. Implications of these understandings for the origin of superconductivity will be discussed.

In the second part of my talk, I will analyze the emerging nematic correlations in the graphene-based moiré systems, and discuss the clues that the nematicity provides for the correlation effects that underlie the insulating and bad metal states in their phase diagram.

Return to schedule