Strain-induced modulation of exchange interaction in monolayer zigzag nanoribbons of B2S

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In this work, the strain modulation of electronic structure and magnetic interaction in monolayer nanoribbons of B2S, a recently realized monolayer system, is investigated. In the first part of our study, we focus on how the electronic structure of monolayer nanoribbons of B2S is modified under uniaxial strains, then employing a tight-binding framework together with the conventional theory of elasticity, we discuss how strain-induced local deformations can be used as a means to affect Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in zigzag nanoribbons of B2S. We show that breaking the inversion symmetry in the unit cell of a zigzag B2S nanoribbon (ZBSNR), e.g. by introducing a staggered sublattice potential, plays a key role in the modulation of its electronic and magnetic properties. More interestingly, for the ZBSNRs belong to the group M = 4p, with M the width of the ZBSNR and p an integer number, one can see that a band gap, in which a pair of near-midgap bands completely detached from the bulk bands is always observed. As a key feature, the position of the midgap bands in the energy diagram of ZBSNRs can be shifted by applying the in-plane strains εx and εy. Moreover, the near-midgap bandwidth monotonically decreased with increasing strength of the strain and increases with the width of the ZBSNR. The energy gap of the ZBSNRs decreased with increasing the applied strain and ribbon width. The spatial and strain dependency of the exchange interaction in various configurations of the magnetic impurities are also evaluated. It is shown that magnetic interactions between adsorbed magnetic impurities in B2S nanoribbons can be manipulated by careful strain engineering of such systems. Our results suggest that these tunable electronic and magnetic properties of ZBSNRs mean they may find applications in spintronics and pseudospin electronics based on monolayer B2S nanoribbons.