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arXiv · 2411.11585

Deep-lying semi-Dirac fermions in hexagonal close-packed cadmium

Alaska Subedi·Kamran Behnia
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Abstract

Semi-Dirac fermions are massless in one direction and massive in the perpendicular directions. Such quasiparticles have been proposed in various contexts in condensed matter. Using first principles calculations, we identify a pair of semi-Dirac bands anti-crossing at $-3$ eV below the Fermi level in the electronic structure of hexagonal close-packed cadmium. The linear out-of-plane dispersion is kept up to the Fermi level. We demonstrate that the dichotomy between the linear and quadratic dispersions is driven by an orientation-sensitive hybridization between the $s$ and $p_z$ orbitals. The upper semi-Dirac band produces a lens-shaped nonellipsoidal Fermi sheet whose cross-section area has a $k$-dependence that is in excellent agreement with the experimentally measured period of Sondheimer oscillations.

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Alaska Subedi, Kamran Behnia. 2024-11-18. Deep-lying semi-Dirac fermions in hexagonal close-packed cadmium. https://doi.org/10.1088/1361-648x%2Fae177b

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