Mitobe Tsubasa, Hoshi Kazuhisa, Kasem Md Riad, Kiyama Ryosuke, Usui Hidetomo, Yamashita Aichi, Higashinaka Ryuji, Matsuda Tatsuma D, Aoki Yuji, Katase Takayoshi, Goto Yosuke, Mizuguchi Yoshikazu
Department of Physics, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, 192-0397, Japan.
Department of Physics and Materials Science, Shimane University, 1060, Nishikawatsucho, Matsue, 690-8504, Japan.
Sci Rep. 2021 Nov 24;11(1):22885. doi: 10.1038/s41598-021-02341-9.
We investigated the chemical pressure effects on structural and electronic properties of SnTe-based material using partial substitution of Sn by AgBi, which results in lattice shrinkage. For Sn(AgBi)Te, single-phase polycrystalline samples were obtained with a wide range of x. On the basis of band calculations, we confirmed that the Sn(AgBi)Te system is basically possessing band inversion and topologically preserved electronic states. To explore new superconducting phases related to the topological electronic states, we investigated the In-doping effects on structural and superconducting properties for x = 0.33 (AgSnBiTe). For (AgSnBi)InTe, single-phase polycrystalline samples were obtained for y = 0-0.5 by high-pressure synthesis. Superconductivity was observed for y = 0.2-0.5. For y = 0.4, the transition temperature estimated from zero-resistivity state was 2.4 K, and the specific heat investigation confirmed the emergence of bulk superconductivity. Because the presence of band inversion was theoretically predicted, and the parameters obtained from specific heat analyses were comparable to In-doped SnTe, we expect that the (AgSnBi)InTe and other (Ag, In, Sn, Bi)Te phases are candidate systems for studying topological superconductivity.
我们通过用AgBi部分替代Sn来研究化学压力对SnTe基材料结构和电子性质的影响，这会导致晶格收缩。对于Sn(AgBi)Te，在很宽的x范围内获得了单相多晶样品。基于能带计算，我们证实Sn(AgBi)Te体系基本具有能带反转和拓扑保持的电子态。为了探索与拓扑电子态相关的新超导相，我们研究了x = 0.33（AgSnBiTe）时In掺杂对结构和超导性质的影响。对于(AgSnBi)InTe，通过高压合成获得了y = 0 - 0.5的单相多晶样品。在y = 0.2 - 0.5时观察到了超导性。对于y = 0.4，从零电阻态估计的转变温度为2.4 K，比热研究证实了体超导的出现。由于理论上预测了能带反转的存在，并且从比热分析获得的参数与In掺杂的SnTe相当，我们预计(AgSnBi)InTe和其他(Ag, In, Sn, Bi)Te相是研究拓扑超导性的候选体系。
