Multiband effects and possible Dirac fermions in Fe1+yTe0.6Se0.4

作者：Sun Yue^*; Taen Toshihiro; Yamada Tatsuhiro; Pyon Sunseng; Nishizaki Terukazu; Shi Zhixiang; Tamegai Tsuyoshi

来源：Physical Review B, 2014, 89(14): 144512.

DOI：10.1103/PhysRevB.89.144512

We investigated the transport properties of Fe1+yTe0.6Se0.4 single crystals with different amounts of excess Fe prepared by O-2 annealing. The O-2 annealing remarkably improved transport properties. In particular, a strongly nonlinear Hall resistivity was observed only in the fully annealed crystal, and the magnetoresistance (MR) was drastically enhanced after annealing, reaching a value larger than 17% at 16 K and 14 T. The obvious change of transport properties after the annealing indicates that the band structure of Fe1+yTe0.6Se0.4 is affected by the excess Fe. The nonlinear Hall resistivity and violation of ( modified) Kohler's scaling of the large MR prove the multiband effects in the Fe1+yTe0.6Se0.4 single crystal. The MR for the fully annealed crystal develops linearly against the magnetic field from the intermediate field (e.g., 2 T at 16 K) to the measurement limit of 14 T. This phenomenon is interpreted by the existence of the Dirac cone state, in which all the Dirac fermions occupy only the lowest Landau level in the quantum limit.

• 出版日期2014-4-24
• 单位东南大学