Journal of the Korean Physical Society

Mott transition in the asymmetric hubbard model at half-filling: Equation of motion approach

Anh-Tuan Hoang, Thi-Thu-Trang Tran, Duc‐Anh Le

Published Jan 1, 2016• 3 citations

Abstract

We investigate the Mott metal-insulator transition in the asymmetric Hubbard model, which may describe the ground states of fermionic atoms trapped in optical lattices. We use the dynamical mean-field theory and the equation of motion approach to calculate the density of states at the Fermi level and the double occupation for various values of the on-site interaction U and the hopping asymmetry r . The critical interaction is also obtained as a function of the hopping asymmetry. Our results are in good agreement with the ones obtained by using the dynamical mean field theory with the exact diagonalization and the quantum Monte Carlo techniques.

DOI: 10.3938/jkps.68.238

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Journal of the Korean Physical Society

Mott transition in the asymmetric hubbard model at half-filling: Equation of motion approach

Anh-Tuan Hoang, Thi-Thu-Trang Tran, Duc‐Anh Le

Published Jan 1, 2016• 3 citations

Publisher

Abstract

DOI: 10.3938/jkps.68.238

Related papers

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1+x

the lower or upper alloy subband is half filled and the system becomes a Mott insulator at strong interactions, with a correlation gap at the Fermi level. At the metal-insulator transition hysteresis is observed. We also analyze the effective theory in the $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Delta}}\ensuremath{\infty}$ limit and find good agreement between analytical and numerical results for the critical interaction

{U}_{c}

at which the metal-insulator transition occurs.

\Delta

is increased. In the other hand, for a fixed

\Delta

U_c

decreases with increasing the mass imbalance. We also show the existence of BI phase in the system for the case

\Delta \ne 0

U=0

and calculate the staggered charge density

n_B − n_A

as a function of the interaction for different values of the mass imbalance. Our results in the limiting cases (

r = 1

;

\Delta \ne 0

or/and

\Delta = 0

;

r\ne 1

) are in good agreement with those obtained from full dynamical mean field theory.

U

at the

d

-orbital and the charge-transfer energy

Δ

between the

d

- and

p

-orbitals. Critical behaviour of the quasiparticle weight is also obtained analytically as a function of

U

and

Δ

. The analytic results are in good agreement with the numerical results of the exact diagonalization method.

t

through the evolution of the magnetic moment, spectral function, internal energy, and specific heat as the interaction

U

and temperature

T

are varied. This work also presents a comparison between DMFT and finite-size determinant quantum Monte Carlo calculations and a discussion of the advantages and limitations of both methods.