Electronic correlations effect on nontrivial topological fermions in CoSi

Abstract

The present study has been carried out to understand the effect of electronic correlations on the recently found fermions in CoSi. For which the spectral functions of bulk and (001) surface of CoSi have been investigated by using DFT+DMFT advanced methodology at T = 100 K with and without inclusion of spin-orbit coupling (SOC). All the newly found fermions are observed at $\Gamma$ and $R$ points similar to other theoretical and experimental reports. Our DFT+DMFT calculations for the bulk states have shown one extra hole pocket at $M$ point. Both coherent and incoherent features have been observed in the spectra of bulk CoSi. This indicates the presence of quasiparticle-quasiparticle (QP-QP) interactions which is eventually affecting the lifetime ($\tau$) of exotic fermionic QPs. For instance, the calculated $\tau$ for QPs at $\omega \sim$ -30 and -186 mev are found to be $\sim 10^{-9}$ s and $\sim 10^{-12}$ s, respectively when SOC is not considered. However, $G_0{W}_0$ corrections have shown $\tau$ for spin-1 fermionic QP at $\Gamma$ to be infinite while for double Weyl fermionic QP at $R$ point to be $\sim 10^{-12}$ s. Their effective masses ($m^{\ast }$) have also been calculated as $\sim$ 1.60 and 1.64 at $\Gamma$ and $R$ points, respectively. Furthermore, the spectral functions at T = 100 K of (001) surface have also shown both coherent and incoherent features. Consequently, at $\omega$ = 0 for surface states $\tau$ has been calculated of the order $\sim 10^{-8}$s for both without SOC and with SOC inclusions.

References in corpus (17)

• The electronic properties of graphene
• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Evidence of Majorana fermions in an Al - InAs nanowire topological superconductor
• Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
• Majorana bound states in a coupled quantum-dot hybrid-nanowire system
• Quantum Monte Carlo Impurity Solver for Cluster DMFT and Electronic Structure Calculations in Adjustable Base
• Quasiparticle self-consistent $GW$ method; a basis for the independent-particle approximation
• Multiple types of topological fermions in transition metal silicides
• Discovery of topological chiral crystals with helicoid arc states
• New classes of chiral topological nodes with non-contractible surface Fermi arcs in CoSi
• Crystal growth and quantum oscillations in the topological chiral semimetal CoSi
• Type-II Weyl Points in Three-Dimensional Cold Atom Optical Lattices
• Temperature dependent correlations in covalent insulators
• Density functional plus dynamical mean field theory of the metal-insulator transition in early transition metal oxides
• Pseudospin 3/2 Fermions, Type-II Weyl Semimetals and Critical Weyl Semimetals in Tricolor Cubic Lattice

Cited by in corpus (1)

• Electrical conductivity and screening effect of spin-1 chiral fermions scattered by charged impurities