Lattice vibrations and electrical transport in (Bi1 −xInx)2Se3 films

We present Raman, terahertz transmission, and transport measurements on (Bi1 −xInx)2Se3films to study the evolution ofphonon modes andresistivity with an increasingindium content across themetal-insulator phase transition. The frequencies of two Raman-active modesEg2 andA1g2 as well as an infrared-active modeEu increase with an increasingindium content due to the smaller atomic weight ofindium compared to bismuth. Terahertz data are fitted by a Drude-Lorentz model. Drude scattering rates increase from 47 to 75  cm−1 with an increasingindium content from 0% to 16% due to stronger impurity scattering. Thecarrier concentration drops significantly forx = 24%. The temperature dependence of theresistivity switches from metallic atx = 16% to insulating atx = 24%, indicating ametal-insulator transition in between.

Source: Applied Physics Letters - November 15, 2016 Category: Physics Authors: Jiajun Zhu, Fang Liu, Shengqiang Zhou, C. Franke, S. Wimmer, V. V. Volobuev, G. Springholz, A. Pashkin, H. Schneider and M. Helm Source Type: research