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arXiv · 1810.12901

Numerical linked-cluster expansions for disordered lattice models

Michael Mulanix·Demetrius Almada·Ehsan Khatami
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Abstract

Imperfections in correlated materials can alter their ground state as well as finite-temperature properties in significant ways. Here, we develop a method based on numerical linked-cluster expansions for calculating exact finite-temperature properties of disordered lattice models directly in the thermodynamic limit. We show that a continuous distribution for disordered parameters can be achieved using a set of carefully chosen discrete modes in the distribution, which allows for the averaging of properties over all disorder realizations. We benchmark our results for thermodynamic properties of the square lattice Ising and quantum Heisenberg models with bond disorder against Monte Carlo simulations and study them as the strength of disorder changes. We also apply the method to the disordered Heisenberg model on the frustrated checkerboard lattice, which is closely connected to Sr$_2$Cu(Te$_{0.5}$W$_{0.5}$)O$_6$. Our method can be used to study finite-temperature properties of other disordered quantum lattice models including those for interacting lattice fermions.

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Michael Mulanix, Demetrius Almada, Ehsan Khatami. 2018-12-13. Numerical linked-cluster expansions for disordered lattice models. https://doi.org/10.1103/physrevb.99.205113

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