FisMat2017 - Submission - View

Abstract's title: Spin-resolved angular-resolved photoemission spectroscopy experiments on in-situ transferred epitaxial Bi2Se3 thin films
Submitting author: Chiara Bigi
Affiliation: Dipartimento di Fisica - UniversitĂ  degli Studi di Milano
Affiliation Address: Via Giovanni Celoria 16, 20133 Milano
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: P.Orgiani (1), P.Kumar Das(2,3), J.Fujii (2), R.Ciancio (2), B.Gobaut (4), A.Galdi (1,5), C.Sacco (1,6), L.Maritato (1,6), P.Torelli (2), G.Panaccione (2), I.Vobornik (2), and G.Rossi (2,7) (1)CNR-SPIN, UOS Salerno, 84084 Fisciano, Italy (2)CNR-IOM, TASC Laboratory, 34139 Trieste, Italy (3)International Centre for Theoretical Physics (ICTP), 34151 Trieste, Italy (4)Elettra Sincrotrone Trieste, 34139 Trieste, Italy (5)Department of Information and Electrical Engineering and Applied Mathematics, University of Salerno,84084 Fisciano, Italy (6)Department of Industrial Engineering, University of Salerno, 84084 Fisciano, Italy (7)Department of Physics, University of Milano, 20133 Milano, Italy

Topological insulators Bi2Se3 thin films have been grown by Pulsed Laser Deposition on (111)-SrTiO3 and (0001)-Al2O3 substrates. X-ray diffraction (XRD) was used to investigate the effects of the substrate temperature (ranging from 270°C up to 400°C) and the background pressure (ranging from 10-5 mbar to 10-1 mbar) on the structural properties of the Bi2Se3 films. XRD investigation demonstrates that epitaxial Bi2Se3 with single (0001)-orientation can be obtained on several substrates in a narrow (i.e. 20°C) range of deposition temperatures at 10-1 mbar of background pressure. In-situ Low-Energy Electron Diffraction (LEED) showed that films grown on (001)-Al2O3 substrates have almost-unique in-plane orientation and good surface quality to perform Spin and Angle-Resolved Photo-Emission Spectroscopy (SARPES) experiments.

In-situ Spin-resolved and conventional ARPES experiments on the topological surface state of Bi2Se3 thin films were performed by using synchrotron radiation. ARPES band dispersion of the Bi2Se3 thin films show a single Dirac cone centered at the Γ point of the Brillouine zone. The spin-resolved spectra confirmed the spin-momentum locking fingerprint of the topological surface state, where opposite spin polarization occurs for opposite momenta. 



Orgiani P. et al Appl. Phys. Lett. 110, 171601 (2017)