Effect of Hubbard U on the construction of low-energy Hamiltonians for LaMnO(3) via maximally localized Wannier functions
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2011Access:
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Kovacik, R. and Ederer, C., Effect of Hubbard U on the construction of low-energy Hamiltonians for LaMnO(3) via maximally localized Wannier functions, PHYSICAL REVIEW B, 84, 7, 075118, 2011Download Item:
Effect of Hubbard U on the construction of low-energy Hamiltonians for LaMnO3 via maximally localized Wannier functions.pdf (Published (publisher's copy) - Peer Reviewed) 710.4Kb
Abstract:
We use maximally localized Wannier functions to construct tight-binding (TB) parametrizations for the e(g) bands of LaMnO(3) based on first-principles electronic structure calculations. We compare two different ways to represent the relevant bands around the Fermi level: (i) a d-p model that includes atomic-like orbitals corresponding to both Mn(d) and O(p) states in the TB basis, and (ii) an effective e(g) model that includes only two e(g)-like Wannier functions per Mn site. We first establish the effect of the Jahn-Teller distortion within the d-p model, and then compare the TB representations for both models obtained from GGA+U calculations with different values of the Hubbard parameter U. We find that in the case of the d-p model the TB parameters are rather independent of the specific value of U, if compared with the mean-field approximation of an appropriate multiband Hubbard Hamiltonian. In contrast, the U dependence of the TB parameters for the effective e(g) model cannot easily be related to a corresponding mean-field Hubbard model, and therefore these parameters depend critically on the specific value of U, and more generally on the specific exchange-correlation functional, used in the electronic structure calculation.
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Grant Number
European Commission
233553
Science Foundation Ireland
SFI-07/YI2/I1051
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http://people.tcd.ie/kovacikrhttp://people.tcd.ie/edererc
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Author: EDERER, CLAUDE; KOVACIK, ROMAN
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American Physical SocietyType of material:
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PHYSICAL REVIEW B;84;
7, 075118;
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