Pseudogap, van Hove Singularity, Maximum in Entropy and Specific Heat for Hole-Doped Mott Insulators

The first indication of a pseudogap in cuprates came from a sudden decrease of NMR Knight shift at a doping-dependent temperature T^*. Since then, experiments have found phase transitions at a lower T^*_phase(δ). Using plaquette cellular dynamical mean-field for the square-lattice Hubbard model at high temperature, where the results are reliable, we show that T^*(δ) shares many features of T^*_phase(δ). The remarkable agreement with several experiments, including quantum critical behavior of the electronic specific heat, supports the view that the pseudogap is controlled by a finite-doping extension of the Mott transition. We propose further experimental tests.
[1] A. Reymbaut, et al., Phys. Rev. Research 1, 023015/1-6 (2019)
https://link.aps.org/doi/10.1103/PhysRevResearch.1.023015