Anderson-Mott transition in a disordered Hubbard model with correlated hopping.

Francesca Battista1 and Liliana Arrachea1

1Departamento de F´ısica, FCEyN, Universidad de Buenos Aires and IFIBA

, Pabell´on I, Ciudad Universitaria, 1428 CABA Argentina

Abstract:

We study the ground state phase diagram of the Anderson-Hubbard model with correlated hopping at half filling. The Hamiltonian has a local Coulomb repulsion U and a disorder potential with local energies randomly distributed in the interval (−W, +W) with equal probability, which act on the singly occupied sites. The hopping process which modifies the number of doubly occupied sites is forbidden. The hopping between nearest-neighbor singly occupied and empty sites or between singly occupied and doubly occupied sites have the same amplitude t. We identify three different phases as functions of the disorder amplitude W and Coulomb interaction strength U > 0: (i) A metallic phase for W = 0 and U < 4t, (ii) an Anderson-localized phase for W 6= 0 and U < 4t as well as for W > U/2 and U > 4t and (iii) a Mott insulator phase for W < U/2 and U > 4t. The phases (i) and (ii) are characterized by a finite number of doublons and a vanishing charge gap between the ground state and the excited states. The phase (ii) is characterized by vanishing number of doublons and a finite gap for the charge excitations.

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https://arxiv.org/pdf/1608.06866.pdf