Near Fermi level electronic structure of Ti3SiC2 revealed by angle-resolved photoemission spectroscopy

An in-depth study of the Fermi surface and electronic structure of the ternary nanolamellar carbide Ti3SiC2 is reported. The outputs of angle-resolved photoemission spectroscopy (ARPES) measured on single crystals and density functional theory calculations are systematically compared. The band structure is found to be dominated by Ti d orbitals near the Fermi level. Band inversions near K points are responsible for the intricate shape of the Ti3SiC2 pockets. Previous theory found that those pockets were giving opposite contributions leading to zero thermoelectric power in polycrystalline samples. Here we directly visualize them by ARPES, describe their precise shape, and examine the way they should behave regarding thermoelectric power. The presence of linear band crossings and the effect of spin-orbit coupling on the near Fermi level electronic structure are discussed, as well as potential consequences for magnetotransport and spin Hall effect.