Flat band and Planckian metal
G. E. Volovik
Low Temperature Laboratory, Aalto University, P. O. Box 15100, FI-00076 Aalto, Finland
Landau Institute for Theoretical Physics, 142432 Chernogolovka, Russia
Abstract
We discuss the recent extension of the Sachdev-Ye-Kitaev
microscopic model [PatelSachdev2019], which demonstrates the
characteristic features of the Khodel-Shaginyan fermion
condensate [KhodelShaginyan1990] - the existence
of the finite region of momenta, where the energy of electrons is exactly
zero (the flat band). The microscopic derivation of the flat band in
this interacting model supports the original idea of Khodel and Shaginyan
based on the phenomenological approach. It also suggests that it is the
flat band, which is responsible for the linear dependence of resistivity
on temperature in "strange metals"