Linearized self-consistent quasiparticle GW method: Application to semiconductors and simple metals

Abstract

We present a code implementing the linearized self-consistent quasiparticle GW method (sc-QPGW) in the LAPW basis. Our approach is based on the linearization of the self-energy around zero frequency which differs it from the existing implementations of the scQPGW method. The linearization allows us to use Matsubaras frequencies instead of real ones. As a result it gives us an advantage in terms of efficiency, allowing us easily switch to the imaginary time representation the same way as in the space time method. The all electron LAPW basis set eliminates the need for pseudopotentials. We discuss the advantages of our approach, such as its N 3 scaling with the system size, as well as its shortcomings.We apply our approach to study electronic properties of selected semiconductors, insulators, and simple metals and show that our code produces results very close to the previously published scQPGW data. Our implementation is a good platform for further many body diagrammatic resummations such as GW+DMFT.

Unusual electronic and vibrational properties in the colossal thermopower material FeSb2

“…However, density functional theory (DFT) predicts a metallic rather than a semiconducting ground state 12 , indicating that a more sophisticated approach is required. Consequently, first principle calculations have been performed using a linearized quasiparticle self-consistent GW and dynamical mean field theory (LQSGW + DMFT) approach 25 – 27 (details are provided in the Supplementary Information). Figure 4 shows the low-energy quasiparticle band structure near the K point (0.26 b * + 0.28 c * ) where the direct bandgap is a minimum.…”

ComDMFT: A massively parallel computer package for the electronic structure of correlated-electron systems

“…One way to construct orthonormal basis set |W Ik from |ψ N k , or to determine U N I (k), is by minimizing total spreads (Ω) defined by see table 1. First, a quasiparticle Hamiltonian (H QP ) is constructed within ab initio linearized quasiparticle self-consistent GW (LQSGW) approximation by using FlapwMBPT [2]. Within LQSGW, GW self-energy and polarizability within random phase approximation are constructed by using LQSGW Green's function (G QP ).…”

Electronic structure and thermoelectric properties of CoAsSb with post-DFT approaches

“…This issue was resolved by i) using real-space plus Matsubara's time implementation 19 of polarizability and self-energy evaluation, which allows considerable time savings as compared to the traditional reciprocal-space plus Matsubara's frequency formulation and ii) extensively usage of Message Passing Interface (MPI) to distribute the computational workload. In this respect, we refer interested reader to our earlier publication 20 where the details of our parallelization strategy for the evaluation of all principal ingredients of GW algorithm are discussed. They are too numerous to elaborate the details here, but we would like to point out about one addition (with respect to what was presented in [20]) which specifically was implemented in the course of our present study.…”

“…In this respect, we refer interested reader to our earlier publication 20 where the details of our parallelization strategy for the evaluation of all principal ingredients of GW algorithm are discussed. They are too numerous to elaborate the details here, but we would like to point out about one addition (with respect to what was presented in [20]) which specifically was implemented in the course of our present study. Namely, the calculation of W for a specific momentum and Matsubara frequency was performed by a process group to distribute peak memory usage.…”