Quantum Oscillation and Electronic Structure of Sn₄As₃ and Sn₄P₃

We report the magnetotransport properties and electronic structures of the single crystals of Sn₄As₃ and Sn₄P₃. The magnetization curves display strong de Haas–van Alphen oscillations at low temperatures and high magnetic fields. The oscillation frequencies and corresponding Fermi surfaces (FSs) are identified from the analysis of the oscillations. The in-plane magnetization of Sn₄As₃ shows the split of FSs induced by nonsymmetric spin–orbit interaction. The extracted cyclotron effective masses are very small and in the range 0.03–0.11 m_e. First-principles calculations reveal the electronic structures and topological properties. Large transverse magnetoresistance (MR) has also been observed in Sn₄As₃ and Sn₄P₃. The Hall measurements eliminate the possibility of electron–hole compensation. It is suggested that the large MR mainly originates from the open FSs.