We study electric transport near the Mott metal-insulator transition. Optical conductivity of the half-filled Hubbard model on a triangular lattice is calculated based on a cellular dynamical mean field theory including vertex corrections inside the cluster. By investigating the spectrum at low frequencies, we find that a Drude peak on the metallic side smoothly connects to an "ingap" peak on the insulating side. The optical weight of these peaks exhibits a critical behavior with power-law near the Mott critical end point, $|D-D^*|\propto|U-U^*|^{1/δ}$ . We find that the critical exponent $1/δ$ differs from the exponents in the thermodynamics.We study electric transport near the Mott metal-insulator transition. Optical conductivity of the half-filled Hubbard model on a triangular lattice is calculated based on a cellular dynamical mean field theory including vertex corrections inside the cluster. By investigating the spectrum at low frequencies, we find that a Drude peak on the metallic side smoothly connects to an "ingap" peak on the insulating side. The optical weight of these peaks exhibits a critical behavior with power-law near the Mott critical end point, $|D-D^*|\propto|U-U^*|^{1/δ}$. We find that the critical exponent $1/δ$ differs from the exponents in the thermodynamics.

arXiv:1111.5371Journal of the Physical Society of JapanJul 17, 20128 citations

Transport criticality at the Mott transition in a triangular-lattice Hubbard model

Toshihiro Sato, Kazumasa Hattori, Hirokazu Tsunetsugu

We study electric transport near the Mott metal-insulator transition in a triangular-lattice Hubbard model at half filling. We calculate optical conductivity $\ensuremath{\sigma}(\ensuremath{\omega})$ based on a cellular dynamical mean-field theory including vertex corrections inside the cluster. Near the Mott critical end point, a Drude analysis in the metallic region suggests that the change in the Drude weight is important rather than that in the transport scattering rate for the Mott transition. In the insulating region, there emerges an ``in-gap'' peak in $\ensuremath{\sigma}(\ensuremath{\omega})$ at low $\ensuremath{\omega}$ near the Mott transition, and this smoothly connects to the Drude peak in the metallic region with decreasing Coulomb repulsion. We find that the weight of these peaks exhibits a power-law behavior upon controlling Coulomb repulsion at the critical temperature. The obtained critical exponent suggests that conductivity does not correspond to magnetization or energy density of the Ising universality class in contrast to several previous works.We study electric transport near the Mott metal-insulator transition in a triangular-lattice Hubbard model at half filling. We calculate optical conductivity $\ensuremath{\sigma}(\ensuremath{\omega})$ based on a cellular dynamical mean-field theory including vertex corrections inside the cluster. Near the Mott critical end point, a Drude analysis in the metallic region suggests that the change in the Drude weight is important rather than that in the transport scattering rate for the Mott transition. In the insulating region, there emerges an ``in-gap'' peak in $\ensuremath{\sigma}(\ensuremath{\omega})$ at low $\ensuremath{\omega}$ near the Mott transition, and this smoothly connects to the Drude peak in the metallic region with decreasing Coulomb repulsion. We find that the weight of these peaks exhibits a power-law behavior upon controlling Coulomb repulsion at the critical temperature. The obtained critical exponent suggests that conductivity does not correspond to magnetization or energy density of the Ising universality class in contrast to several previous works.

arXiv:1212.1227Physical Review BDec 21, 201217 citations

MOTT TRANSITION IN THE HUBBARD MODEL

B. Sriram Shastry

WORLD SCIENTIFIC eBooksApr 1, 19930 citations

|D-D^*|\propto|U-U^*|^{1/δ}

. We find that the critical exponent

1/δ

differs from the exponents in the thermodynamics.