Anomalous phonon softening in the topological insulator Sn-doped Bi1.1Sb0.9Te2S

作者：BoWen Li,WenChao Jiang,GuanYu Chen,Ying Xiang,Wei Xie,YaoMin Dai,XiYu Zhu,Huan Yang,Hai-Hu Wen

摘要：Investigations into the phonon behavior provide important information on interactions between different excitations in quantum materials.We perform a detailed study of the phonon behavior in the topological insulator Sn-doped Bi1.1Sb0.9Te2S using infrared spectroscopy.We observe two IR-active phonon modes at about 64 and 165 cm^1,which are labeled withαandβ,respectively.While the evolution of theβmode with temperature can be well described by the expected anharmonic decay process,theαmode shifts to lower frequencies with decreasing temperature.Such an anomalous softening of theαmode may arise from the charged-phonon effect due to the coupling between this mode and the topological surface states in Sn-doped Bi1.1Sb0.9Te2S.

发文机构：Center for Superconducting Physics and Materials

关键词：topologicalinsulatorinfraredspectroscopyPHONON

分类号： O469[理学—凝聚态物理]