Rashba coupling amplification by a staggered crystal field

By means of ARPES and first-principles calculations, we give evidence of a large Rashba coupling leading to a remarkable band splitting in centrosymmetric  BaNiS2. This is explained by a huge staggered crystal field that breaks inversion symmetry at the Ni site.

  Santos-Cottin et al., Nat. Commun. 7, 11258 (2016).

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We have investigated the giant Rashba-Dresselhaus spin-splitting of the electronic band structure of the centrosymmetric bulk BaNiS2 crystal by means of angle-resolved photoemission spectroscopy (ARPES) supported by ab initio calculations. The system is composed by light elements so the spin-orbit coupling could not account for the measured remarkable band splitting of ΔE ≈ 150 meV. This  is  explained  by a  huge staggered crystal field of 1.4 V/Å, produced by a gliding plane symmetry, that breaks inversion symmetry at the Ni site. This  unexpected  result  in  the  absence  of  heavy elements demonstrates an effective mechanism of Rashba coupling amplification that may foster spin-orbit band engineering.
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Rashba coupling amplification by a staggered crystal field
D. Santos-Cottin,  M. Casula, G. Lantz, Y. Klein, L. Petaccia, P. Le Fèvre, F. Bertran, E. Papalazarou, M. Marsi, A. Gauzzi,
Nat. Commun. 7, 11258 (2016).
doi: 10.1038/ncomms11258

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