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 $T^{\ast }(\delta )$. Since then, experiments have found phase transitions at a lower $T_{\text{phase}}^{\ast }(\delta )$. Using plaquette cellular dynamical mean-field for the square-lattice Hubbard model at high temperature, where the results are reliable, we show that $T^{\ast }(\delta )$ shares many features of $T_{\text{phase}}^{\ast }(\delta )$. 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.