Coexistence of Dirac fermion and charge density wave in the square-net-based semimetal LaAuSb2

We report a comprehensive study of magnetotransport properties, angle-resolved photoemission spectroscopy (ARPES), and density functional theory (DFT) calculations on self-flux grown LaAuSb2 single crystals. Resistiv-ity and Hall measurements reveal a charge density wave (CDW) transition at 77 K. MR and de Haas-van Alphen measurements indicate that the transport properties of LaAuSb2 are dominated by Dirac fermions that arise from Sb square nets. ARPES measurements and DFT calculations reveal an electronic structure with a common feature of the square-net-based topological semimetals, which is in good agreement with the magnetotransport properties. Our results indicate the coexistence of CDW and Dirac fermion in LaAuSb2, both of which are linked to the bands arising from the Sb square net, suggesting that the square net could serve as a structural motif to explore various electronic orders.