Fig. 6
Spin and charge conversion in new types of 3D topological insulators. a Surface states of α-Sn (001) films (~30 monolayers) measured by ARPES. α-Sn (001) films are grown on InSb (001) substrate by molecular beam epitaxy. b The FMR spectrum and charge current measured on InSb/α-Sn/Ag/Fe/Au sample. Ag layer is used to protect the topological surface states from degradation by the growth of Fe layer. c Comparison of topological Kondo insulator (SmB6) with Bi2Se3 type topological insulators. Inset: crystalline structure of SmB6. TSS/BCB stands for topological surface states and bulk conducting bands. d The resistance of the SmB6 single crystal as a function of temperature. Green background highlights the region where pure surface states exist. Inset: measurement of the spin and charge conversion via spin pumping from Py. e Magnetic field dependence of voltages on the SmB6/Py device measured at T = 0.84, 1.66, 2.1, 2.3, and 10 K, respectively. The measurement is performed under microwave frequency of 10.1 GHz. (a, b adapted from ref. 87 with permission, copyright American Physical Society 2016) (c adapted from ref. 93 with permission, copyright Springer Nature 2014) (d, e adapted from ref. 96 with permission, copyright Springer Nature 2016)
