Low-energy effective Hamiltonians for correlated electron systems beyond density functional theory

Article

关键词: MEAN-FIELD THEORY;    RENORMALIZATION-GROUP;    MATRIX RENORMALIZATION;    WAVE-FUNCTIONS;    SUPERCONDUCTIVITY;    CA1-XSRXVO3;    TRANSITION;    PRINCIPLES;    SATELLITES;    STATES;   

DOI  :  10.1103/PhysRevB.96.075102

来源: SCIE

【 摘 要 】

We propose a refined scheme of deriving an effective low-energy Hamiltonian for materials with strong electronic Coulomb correlations beyond density functional theory (DFT). By tracing out the electronic states away from the target degrees of freedom in a controlled way by a perturbative scheme, we construct an effective Hamiltonian for a restricted low-energy target space incorporating the effects of high-energy degrees of freedom in an effective manner. The resulting effective Hamiltonian can afterwards be solved by accurate many-body solvers. We improve this multiscale ab initio scheme for correlated electrons (MACE) primarily in two directions by elaborating and combining two frameworks developed by Hirayama et al. [M. Hirayama, T. Miyake, and M. Imada, Phys. Rev. B 87, 195144 (2013)] and Casula et al. [M. Casula, P. Werner, L. Vaugier, F. Aryasetiawan, T. Miyake, A. J. Millis, and S. Biermann, Phys. Rev. Lett. 109, 126408 (2012)]: (1) Double counting of electronic correlations between the DFT and the low-energy solver is avoided by using the constrained GW scheme; and (2) the frequency dependent interactions emerging from the partial trace summation are successfully separated into a nonlocal part that is treated following ideas by Hirayama et al. and a local part treated nonperturbatively in the spirit of Casula et al. and are incorporated into the renormalization of the low-energy dispersion. The scheme is favorably tested on the example of SrVO3.

【 授权许可】

Free