Comment on: Locally self-consistent embedding approach for disordered electronic systems

TL;DR

This paper critiques a recent embedding scheme for disordered systems, clarifies its relation to their super-cell approximation, and demonstrates their method's effectiveness in capturing electron localization in disordered alloys.

Contribution

The authors show that the recent embedding scheme is a truncated version of their super-cell approximation and demonstrate their method's advantages in modeling electron localization.

Findings

Their super-cell methods effectively capture electron localization.

The embedding scheme is a special case of their super-cell approximation.

Their approach outperforms other methods like DCA in certain regimes.

Abstract

We comment on article by Yi Zhang , Hanna Terletska, Ka-Ming Tam, Yang Wang, Markus Eisenbach, Liviu Chioncel, and Mark Jarrell [Phys. Rev. B {\bf 100}, 054205 (2019)]\cite{Zhang} in which to study substitution disordered systems, they presented an embedding scheme for the locally self-consistent method. Here we show that their methods is a truncated case of our super-cell approximation, achieved by neglecting super-cell wave vectors dependence on self-energy $\Sigma_{sc}({\bf K}_{n},E)$ and replacing them by a local on-site self-energy, $\Sigma_{sc}({\bf K}_{n},E)=\Sigma_{sc}(L,L,E)$ in our articles\cite{Moradian01, Moradian02, Moradian03}. Also their real and k-space self-energies in the limit of the number of super-cell sites, $N_{c}$, approaching the number of lattice sites, N, do not recover exact self-energies $\Sigma(l, l', E)$ and $\Sigma({\bf k}, E)$. For highlighting advantages of our methods with respect to other approximations such as dynamical cluster approximation (DCA)\cite{Jarrell} in capturing electron localization, we apply our real space super-cell approximation (SCA), and super-cell local self-energy approximation (SCLSA) to one and two dimensional substitution disorder alloy systems. Our electron localization probability calculations for these systems determine non zero values that indicate electrons localization.