Massive Dirac Fermion Observed in Lanthanide-Doped Topological Insulator Thin Films

The breaking of time reversal symmetry (TRS) in three-dimensional (3D) topological insulators (TIs), and thus the opening of a ‘Dirac-mass gap’ in the linearly dispersed Dirac surface state, is a prerequisite for unlocking exotic physical states. Introducing ferromagnetic long-range order by transit...

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Detalles Bibliográficos
Autores principales: Harrison, S. E., Collins-McIntyre, L. J., Schönherr, P., Vailionis, A., Srot, V., van Aken, P. A., Kellock, A. J., Pushp, A., Parkin, S. S. P., Harris, J. S., Zhou, B., Chen, Y. L., Hesjedal, T.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4621505/
https://www.ncbi.nlm.nih.gov/pubmed/26503435
http://dx.doi.org/10.1038/srep15767
Descripción
Sumario:The breaking of time reversal symmetry (TRS) in three-dimensional (3D) topological insulators (TIs), and thus the opening of a ‘Dirac-mass gap’ in the linearly dispersed Dirac surface state, is a prerequisite for unlocking exotic physical states. Introducing ferromagnetic long-range order by transition metal doping has been shown to break TRS. Here, we present the study of lanthanide (Ln) doped Bi(2)Te(3), where the magnetic doping with high-moment lanthanides promises large energy gaps. Using molecular beam epitaxy, single-crystalline, rhombohedral thin films with Ln concentrations of up to ~35%, substituting on Bi sites, were achieved for Dy, Gd, and Ho doping. Angle-resolved photoemission spectroscopy shows the characteristic Dirac cone for Gd and Ho doping. In contrast, for Dy doping above a critical doping concentration, a gap opening is observed via the decreased spectral intensity at the Dirac point, indicating a topological quantum phase transition persisting up to room-temperature.