Ab initio calculations of structural, electronic, optical, and magnetic properties of delafossite SMoO2 (S = Na, K, Rb, Cs) for spintronics

Abstract

Half metallic ferromagnetic (HMF) are key materials for quantum computing information storage devices and green energy. So, the structural, electronic, optical, and magnetic properties of SMoO2 (S = Na, K, Rb, Cs) are studied by quantum simulations based on density functional theory (DFT) within WIEN2K code. The Perdew − Burke − Ernzerhof (PBE + GGA) was used for the exchange correlation potential to study the said compounds. The volume optimization properties indicated that these compounds have minimum ground state energy in monoclinic crystal structure with space group 12 C2/m. Moreover, electronic band gap properties and density of states (DOS) graphs depicted the metallic nature for spin up a channel and semiconductor nature for spin down channel. This confirms the half-metallic ferromagnetism (HMF), and Heisenberg's classical model confirms the 100% spin polarization. Various frequency dependent optical parameters explain the optical properties. The double exchange process, crystal field energy ∆Ecry, direct Δx(d), and indirect exchange energies Δx(pd), is demonstrated by the quantum ferromagnetic behavior. The negative value of Δx(pd) and magnetic exchange constants confirm the ferromagnetism due to the quantum exchange mechanism of electrons. In addition to the above, it has been noted from the density of states that Mo d-states are responsible for the response of half metallic nature of these compounds. The magnetic parameter values of SMoO2 (S = Na, K, Rb, and Cs) show higher magnetic moment and major contribution coming from the Mo atom. Hence the studied results show that these compounds are valuable materials for spintronic applications.