Magnetotransport properties and topological phase transition in NaCd4As3

We report the magnetotransport properties and the electronic structure of $\mathrm{Na}{\mathrm{Cd}}₄{\mathrm{As}}₃$ single crystal. The electric resistivity of $\mathrm{Na}{\mathrm{Cd}}₄{\mathrm{As}}₃$ exhibits a metallic behavior. Clear Shubnikov--de Haas (SdH) oscillations have been observed at low temperatures and high magnetic fields. A single fundamental frequency and small cyclotron effective mass are obtained from the analysis of SdH oscillations, which originate from an ellipsoidal Fermi surface. The Hall resistivity reveals the multiband nature at low temperature and the electron carriers dominate the transport properties. First-principles calculations show that the electronic structure of $\mathrm{Na}{\mathrm{Cd}}₄{\mathrm{As}}₃$ undergoes a topological phase transition from topological crystalline insulator (TCI) to topological insulator (TI) induced by the structural phase transition. The breaking of mirror symmetry is considered to play a key role in the topological phase transition. Our findings show that $\mathrm{Na}{\mathrm{Cd}}₄{\mathrm{As}}₃$ is a suitable platform to study the effect of mirror symmetry on the band topology of TCI.