An efficient impurity solver in DMFT for multi-band systems

Although several impurity solvers in DMFT[1] have been proposed, especially in multi-band systems, there are practical difficulties arising from a trade-off between numerical costs and reliability. In this study, we re-interpret the iterative perturbation theory(IPT)[2] from the perspective of the frequency dependence of the two-particle full-vertex, and extend it such that costs and reliability can be compatible. We validate our method by comparing them with several numerically exact methods. As a result, we confirm that the results of our method show good agreements with that of the exact methods, not only in single-band systems but also in multi-band systems. In the presentation, we explain the details of the method, and show the results of benchmarks.

Reference

[1] A. Georges, et al.: Rev. Mod. Phys. 68 (1996)13.

[2] H. Kajueter et al.: Phys. Rev. Lett. 77 (1996) 131.

[3] R. Mizuno, M. Ochi, and K. Kuroki, Phys. Rev. B 104, 035160 (2021).