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The half filled Hubbard model describes interacting electrons with one
electron on average per site. On a two dimensional square lattice, the half
filled Hubbard model supports a Mott insulating state where electrons are
predominantly site localized. A very di↵erent kind of insulating state, the
Anderson insulator, occurs when non interacting electrons hop in pres-
ence of static potential disorder, again on a 2D square lattice. Curiously
enough, if we have interacting electrons hopping in presence of potential
disorder, the two insulating agencies conspire to give rise to a metal at
zero temperature.
In this talk, I will discuss the nature and fate of the ensuing metal at
finite temperatures. For this we will study the Anderson-Hubbard model
using a recently developed technique called the ’Mean-Field-Monte Carlo’
(MF-MC) approach [1, 2], that allows studying interacting electron prob-
lems at arbitrary interaction strengths and temperature. I will briefly
discuss some benchmarks of the MF-MC method and then discuss our
results for the Anderson-Hubbard model [3]. I will show that the disorder
induced metal is generically a non-Fermi liquid whose characteristics can
be tuned continuously by changing interaction and disorder strengths. All
metallic states obtained in this fashion show clear deviation from Fermi
liquid prediction of T 2 dependence of resistivity on temperature and ex-
hibit logarithmic divergence of the specific heat over wide temperature
ranges. I will end by discussing the reason for the non Fermi liquid be-
havior, its tunability and relevance to strongly correlated materials.
References:
[1] A. Mukherjee, et. al., Phys. Rev. B 90, 205133 (2014).
[2] A. Mukherjee, et. al.,Phys. Rev. E 91, 063303 (2015).
[3] N. D. Patel, et. al. ”Phys. Rev. Lett. 119, 086601 (2017). |