We report the magnetoresistance(MR), de Haas-van Alphen (dHvA) oscillations and the electronic structures of single crystal PtGa. The large unsaturated MR is observed with the magnetic field B//[111]. Evident dHvA oscillations with B//[001] configuration have been observed, from which twelve fundamental frequencies are extracted and the spin-orbit coupling effect (SOC) induced band splitting is revealed. The light cyclotron effective masses are extracted from the fitting by the thermal damping term of the Lifshitz-Kosevich (LK) formula. Combining with the calculated frequencies from the first-principles calculations, the dHvA frequencies F$_1$/F$_3$ and F$_{11}$/F$_{12}$ are confirmed to originate from the electron pockets at $\Gamma$ and R, respectively. The first-principles calculations also reveal the existence of spin-3/2 RSW fermion and time-reversal (TR) doubling of the spin-1 excitation at $\Gamma$ and R with large Chern number $\pm4$ when SOC is included.

中文翻译：

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大陈数拓扑手征半金属 PtGa 中的量子振荡和电子结构

我们报告了单晶 PtGa 的磁阻 (MR)、de Haas-van Alphen (dHvA) 振荡和电子结构。用磁场 B//[111] 观察到大的不饱和 MR。已经观察到明显的具有 B//[001] 配置的 dHvA 振荡，从中提取了 12 个基频，并揭示了自旋轨道耦合效应 (SOC) 引起的带分裂。通过 Lifshitz-Kosevich (LK) 公式的热阻尼项从拟合中提取轻回旋加速器有效质量。结合第一性原理计算得出的频率，确定 dHvA 频率 F$_1$/F$_3$ 和 F$_{11}$/F$_{12}$ 源自 $ 处的电子袋\Gamma$ 和 R，分别。