title: Anomalous photoelectric effect of a polycrystalline topological insulator film.
abstract: A topological insulator represents a new state of quantum matter that possesses an insulating bulk band gap as well as a spin-momentum-locked Dirac cone on the surface that is protected by time-reversal symmetry. Photon-dressed surface states and light-induced surface photocurrents have been observed in topological insulators. Here, we report experimental observations of an anomalous photoelectric effect in thin films of Bi2Te3, a polycrystalline topological insulator. Under illumination with non-polarised light, transport measurements reveal that the resistance of the topological surface states suddenly increases when the polycrystalline film is illuminated. The resistance variation is positively dependent on the light intensity but has no relation to the applied electric field; this finding can be attributed to the gap opening of the surface Dirac cone. This observation of an anomalous photoelectric effect in polycrystalline topological insulators offers exciting opportunities for the creation of photodetectors with an unusually broad spectral range. Moreover, polycrystalline topological insulator films provide an attractive material platform for exploring the nature and practical application of topological insulators.
authors: 1] State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics &Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P. R. China [2].
authors: Hongbin
authors: H
authors: Zhang
authors: 1] State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics &Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P. R. China [2].
authors: Jiandong
authors: J
authors: Yao
authors: 1] State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics &Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P. R. China [2].
authors: Jianmei
authors: J
authors: Shao
authors: State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics &Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P. R. China.
authors: Hai
authors: H
authors: Li
authors: State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics &Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P. R. China.
authors: Shuwei
authors: S
authors: Li
authors: State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics &Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P. R. China.
authors: Dinghua
authors: D
authors: Bao
authors: State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics &Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P. R. China.
authors: Chengxin
authors: C
authors: Wang
authors: State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics &Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P. R. China.
authors: Guowei
authors: G
authors: Yang