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Strain induced electronic and magnetic transition in S = 3/2 antiferromagnetic spin chain compound LaCrS3

Exploring the physics of low-dimensional spin systems and their pressure-driven electronic and magnetic transitions are thriving research field in modern condensed matter physics. In this context, recently antiferromagnetic Cr-based compounds such as CrI3, CrBr3, CrGeTe3 have been investigated experimentally and theoretically for their possible spintronics applications. Motivated by the fundamental and industrial importance of these materials, we theoretically studied the electronic and magnetic properties of a relatively less explored Cr-based chalcogenide, namely LaCrS3 where 2D layers of magnetic Cr3+ ions form a rectangular lattice. We employed density functional theory + Hubbard U approach in conjunction with constrained random-phase approximation (cRPA) where the later was used to estimate the strength of U. Our findings at ambient pressure show that the system exhibits semiconducting antiferromagnetic ground state with a gap of 0.5 eV and large Cr moments that corresponds to nominal S=3/2 spin-state. The 1st nearest neighbor (NN) interatomic exchange coupling (J1) is found to be strongly antiferromagnetic (AFM), while 2nd NN couplings are relatively weaker ferromagnetic (FM), making this system a candidate for 1D non-frustrated antiferromagnetic spin-chain family of materials. Based on orbital resolved interactions, we demonstrated the reason behind two different types of interactions among 1st and 2nd NN despite their very similar bond lengths. We observe a significant spin-orbit coupling effect, giving rise to a finite magneto crystalline anisotropy, and Dzyaloshinskii-Moriya (DM) interaction. Further, we found that by applying uniaxial tensile strain along crystallographic a and b-axis, LaCrS3 exhibits a magnetic transition to a semi-conducting FM ground state, while compression gives rise to the realization of novel gapless semiconducting antiferromagnetic ground state.