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arXiv · 1906.10581

Tuning the electronic structure and magnetic coupling in armchair B$_2$S nanoribbons using strain and staggered sublattice potential

Moslem Zare
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Abstract

Monolayer B$_2$S has been recently unveiled as a desirable honeycomb monolayer with an anisotropic Dirac cone. We investigate the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction, between two magnetic impurity moments in armchair-terminated B$_2$S nanoribbons in the presence of strain and staggered sublattice potential. By using an accurate tight-binding model, we firstly study the electronic properties of all infinite-length armchair B$_2$S nanoribbons (ABSNRs), with different edges, in the presence of both strain and staggered potential. The ABSNRs show different electronic and magnetic behaviors due to different edge morphologies. The band gap energy of ABSNRs depends strongly upon the applied staggered potential and thus one can engineer the electronic properties of the ABSNRs via tuning the external staggered potential. A complete and fully reversible semiconductor (or insulator) to metal transition has been observed via tuning the external staggered potential, which can be easily realized experimentally. A prominent feature is the presence of a quasiflat edge mode, isolated from the bulk modes in the ABSNRs belong to the family $M=6p$, with $M$ the width of the ABSNR and $p$ an integer number. The position of the quasi-flatbands(QFBs) in the energy diagram of ABSNRs can be shifted by applying the in-plane strains. At a critical staggered potential, for nanoribbons of arbitrary width, the QFB changes to a perfect flatband. The RKKY interaction has an oscillating behaviour in terms of the applied staggered potentials and width of the ribbon, such that for two magnetic adatoms randomly distributed on the surface of an ABSNR the staggered potential can reverse the RKKY from antiferromagnetism to ferromagnetism and vice versa. Our findings pave the way for applications in spintronics and pseudospin electronics devices based on ABSNRs.

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Moslem Zare. 2019-06-25. Tuning the electronic structure and magnetic coupling in armchair B$_2$S nanoribbons using strain and staggered sublattice potential. https://doi.org/10.1016/j.cocom.2019.e00424

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