Regensburg 2007 – scientific programme

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O: Fachverband Oberflächenphysik

O 34: Methods: Atomic and Electronic Structure I

O 34.6: Talk

Tuesday, March 27, 2007, 17:00–17:15, H42

Spin-orbit coupling in the band structures of the layered charge-density-wave compunds 1T-TaS₂ and 2H-TaSe₂ — •Kai Rossnagel¹ and Neville Smith² — ¹Institut für Experimentelle und Angewandte Physik, Universität Kiel, D-24098 Kiel, Germany — ²Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

Empirical tight-binding calculations on the layered charge-density-wave materials 1T-TaS₂ and 2H-TaSe₂ have been performed and are found to replicate the basic phenomenology of the electronic structure near the Fermi level as revealed by angle-resolved photoelectron spectroscopy (ARPES). In the case of 1T-TaS₂, the combination of spin-orbit coupling and the √13 × √13 reconstruction generates a distinct and very narrow band at the Fermi level [1]. For 2H-TaSe₂, the large spin-orbit splitting of the Ta 5d levels causes a significant change of Fermi surface topology and the combination of spin-orbit coupling and the 3 × 3 reconstruction gives rise to Fermi surface sheet-dependent energy gapping [2]. Our results highlight the importance of spin-orbit interaction in any understanding of the correlation effects and charge-density-wave transitions in these two materials.

[1] K. Rossnagel and Neville V. Smith, Phys. Rev. B 73, 073106 (2006).

[2] K. Rossnagel and Neville V. Smith, to be published.