Chiral Crystal Structure and Split Fermi Surface Properties in TaSi

概要

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We carried out a de Haas--van Alphen (dHvA) experiment in TaSi<inf>2</inf>with the hexagonal chiral structure, together with an energy band calculation. The Fermi surface is found to be split into two different Fermi surfaces, reflecting the non-centrosymmetric crystal structure. The magnitude of the antisymmetric spin--orbit interaction or the splitting energy between the two Fermi surfaces is determined to be 493 K for dHvA branch \alpha (\alpha'), 564 K for branch \beta (\beta'), and 617 K for branch \gamma (\gamma'), where these dHvA branches correspond to the main Fermi surfaces. The present splitting values are compared with 19, 39, and 110 K, respectively, observed in a similar compound, VSi<inf>2</inf>. The splitting energy is found to be larger in Ta-5d conduction electrons than in V-3d conduction electrons. Furthermore, we found a magnetic breakthrough effect for branches \gamma (\gamma') and \alpha (\alpha'), of which the circulating orbits are separate but are nearly degenerate in three and two regions, respectively.
2013-11-15