Electronic and magnetic properties of building blocks of Mn and Fe atomic chains on Nb(110)

Magnetic impurities on a superconducting surface create so-called Yu-Shiba-Rusinov (YSR) states. In magnetic atomic chains, hybridized YSR states develop into bands that can give rise to topological superconductivity and Majorana bound states [1]. Beck et al. recently demonstrated that the YSR states hybridize not only for ferromagnetic but also for antiferromagnetic Mn atomic dimers on a Nb(110) surface due to the presence of spin-orbit coupling [2]. Motivated by this, in the present work the electronic and magnetic structures of Mn and Fe building blocks of atomic chains on a Nb(110) surface are analyzed based on theoretical calculations [3]. Most notably, a spin-spiral ground state is obtained for Fe chains along the Nb[1-10] direction due to the frustration of the isotropic exchange interactions. Here, a flat spin-spiral dispersion relation is identified, which can stabilize spin spirals with various wave vectors together with the magnetic anisotropy.

[1] Kim et al. Sci. Adv. 4, eaar5251 (2018).

[2] Beck et al. Nat. Commun. 12, 2040 (2021).

[3] Lászlóffy et al. Nanomater. 11, 1933 (2021).