Signatures of hidden quantum criticality in the high-temperature charge transport near the mott transition

Abstract

The Mott metal-insulator transition is one of the hallmarks of strong electronic correlation and is one of the most active areas of condensed matter research today. Both the experimental data and theory clearly show that the Mott transition is a rst order transition, featuring a coexistence region up to some critical temperature Tc. The vicinity of the critical point has been studied extensively and is shown to display critical phenomena of the classical Ising universality class. Below Tc, the rst order transition separates a paramagnetic Mott insulator and a paramagnetic metal. At lowest temperature, the two phases often develop long-range order - antiferromagnetism or superconductivity. The Mott transition separates two distinct phases all the way down to zero temperature, which makes it a quantum phase transition. The open questions regarding the Mott transition include: can Mott mechanism in some cases produce a phenomenology drastically dierent from that of a rst order transition? Can Tc be brought down to zero, i.e. can Mott transition be reduced to a single quantum critical point? The theory suggests that these are quite possible, but a clear experimental verication of such prediction is still lacking. Can a Mott transition be completely hidden by a superconducting ordering instability, and can critical uctuations of a Mott transition provide a boost to the Cooper pairing mechanism? These questions are of utmost importance, but are notoriously hard to answer. Is there a universal high-temperature behavior in connection with the Mott transition, as is usually the case with other quantum phase transitions? Here we investigate this possibility and show that the answer is positive. Furthermore, we show that the linear temperature dependence of resistivity often found in the incoherent (bad metal) transport regime can be understood as the general consequence of the Mott quantum criticality. In this thesis we numerically solve the single-site dynamical mean eld (DMFT) equation for the Hubbard model, using the iterative perturbation theory (IPT) and continuous time quantum Monte Carlo (CTQMC). We focus on the supercritical...

Мотов метал-изолатор прелаз је једна од најважнијих последица јаких елек- тронских корелација, и једна од најактивнијих области истраживања у физици кондензоване материје. И експеримент и теорија јасно указују да је Мотов прелаз фазни прелаз првог реда и да испољава коегзистенцију фаза до неке критичне температуре Тц. Транспортне и термодинамичке особине у околини критичне тачке су детаљно проучаване и показало се да могу да се опишу теоријом класичних фазних прелаза...