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Journal articles
Magnetotransport in Bi$_2$ Se$_3$ thin films epitaxially grown on Ge(111)
Abstract : Topological insulators (TIs) like Bi$_2$Se$_3$ are a class of material with topologically protected surface states in which spin-momentum locking may enable spin-polarized and defect-tolerant transport. In this work, we achieved the epitaxial growth of Bi$_2$Se$_3$ thin films on germanium, which is a key material for microelectronics. Germanium also exhibits interesting properties with respect to the electron spin such as a spin diffusion length of several micrometers at room temperature. By growing Bi$_2$Se$_3$ on germanium, we aim at combining the long spin diffusion length of Ge with the spin-momentum
locking at the surface of Bi$_2$Se$_3$. We first performed a thorough structural analysis of Bi$_2$Se$_3$ films using electron and x-ray diffraction as well as atomic force microscopy. Then, magnetotransport measurements at low temperature showed the signature of weak antilocalization as a result of two-dimensional transport in the presence of spinorbit coupling. We interpret our results as the signature of magnetotransport in a single strongly coupled coherent channel in the presence of surface to bulk scattering. Interestingly, the magnetotransport measurements also point out that the conduction channel can be tuned between the Bi$_2$Se$_3$ film and the Ge layer underneath by means of the bias voltage or the applied magnetic field. This result suggests that the Bi$_2$Se$_3$/Ge junction is a promising candidate for tuning spin-related phenomena at interfaces
between TIs and semiconductors.
Cited literature [37 references]
https://hal-cea.archives-ouvertes.fr/cea-02044793
Contributor : Alain Marty <>
Submitted on : Thursday, February 21, 2019 - 4:21:09 PM
Last modification on : Wednesday, August 26, 2020 - 5:54:03 PM
Long-term archiving on: : Wednesday, May 22, 2019 - 9:53:30 PM
Contributor : Alain Marty <>
Submitted on : Thursday, February 21, 2019 - 4:21:09 PM
Last modification on : Wednesday, August 26, 2020 - 5:54:03 PM
Long-term archiving on: : Wednesday, May 22, 2019 - 9:53:30 PM
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