We have used grazing-angle infrared spectroscopy with polarized radiation to detect the Berreman effect (BE) in the two-dimensional electron systems (2DES) which form spontaneously at two interfaces: one between an amorphous film LaAlO3 and its SrTiO3 substrate (LAO/STO), and another at the interface between the topological insulator (TI) Bi2Se3 and its sapphire substrate. In both systems we have thus extracted the 2DES parameters at different temperatures. In the quasi-2DES under amorphous LAO, the surface density ns is higher than under crystalline LAO, while the mobility is nearly the same and the thickness d is 7 nm. In ultrapure Bi2Se3 on sapphire, preliminary data provided d < 1 nm and ns ≈ 1013 cm−2, indicating, by comparison with existing estimates, that the BE indeed detects the topological surface states.

Infrared spectroscopy of two-dimensional electron systems / Calvani, P.; Kalaboukhov, A.; Shibayev, P. P.; Salehi, M.; Moon, J.; Oh, S.; Falsetti, E.; Ortolani, M.; Granozio, F. M.; Brubach, J. -B.; Roy, P.; Nucara, A.. - In: THE EUROPEAN PHYSICAL JOURNAL. SPECIAL TOPICS. - ISSN 1951-6355. - 228:3(2019), pp. 669-673. [10.1140/epjst/e2019-800145-7]

Infrared spectroscopy of two-dimensional electron systems

Calvani P.;Falsetti E.;Ortolani M.;Nucara A.
2019

Abstract

We have used grazing-angle infrared spectroscopy with polarized radiation to detect the Berreman effect (BE) in the two-dimensional electron systems (2DES) which form spontaneously at two interfaces: one between an amorphous film LaAlO3 and its SrTiO3 substrate (LAO/STO), and another at the interface between the topological insulator (TI) Bi2Se3 and its sapphire substrate. In both systems we have thus extracted the 2DES parameters at different temperatures. In the quasi-2DES under amorphous LAO, the surface density ns is higher than under crystalline LAO, while the mobility is nearly the same and the thickness d is 7 nm. In ultrapure Bi2Se3 on sapphire, preliminary data provided d < 1 nm and ns ≈ 1013 cm−2, indicating, by comparison with existing estimates, that the BE indeed detects the topological surface states.
2019
two-dimesional systems; Berreman; infrared
01 Pubblicazione su rivista::01a Articolo in rivista
Infrared spectroscopy of two-dimensional electron systems / Calvani, P.; Kalaboukhov, A.; Shibayev, P. P.; Salehi, M.; Moon, J.; Oh, S.; Falsetti, E.; Ortolani, M.; Granozio, F. M.; Brubach, J. -B.; Roy, P.; Nucara, A.. - In: THE EUROPEAN PHYSICAL JOURNAL. SPECIAL TOPICS. - ISSN 1951-6355. - 228:3(2019), pp. 669-673. [10.1140/epjst/e2019-800145-7]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1399137
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