Topological quantum phase transition from mirror to time reversal symmetry protected topological insulator.

Autor:	Mandal PS; Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Strasse 15, 12489, Berlin, Germany.; Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht Street 24/25, 14476, Potsdam, Germany., Springholz G; Institute for Semiconductor and Solid State Physics, Johannes Kepler Universität, Altenberger Strasse 69, 4040, Linz, Austria., Volobuev VV; Institute for Semiconductor and Solid State Physics, Johannes Kepler Universität, Altenberger Strasse 69, 4040, Linz, Austria.; National Technical University 'Kharkiv Polytechnic Institute', Frunze Street 21, 61002, Kharkiv, Ukraine., Caha O; Department of Condensed Matter Physics, Masaryk University, Kotlářská 267/2, 61137, Brno, Czech Republic., Varykhalov A; Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Strasse 15, 12489, Berlin, Germany., Golias E; Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Strasse 15, 12489, Berlin, Germany., Bauer G; Institute for Semiconductor and Solid State Physics, Johannes Kepler Universität, Altenberger Strasse 69, 4040, Linz, Austria., Rader O; Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Strasse 15, 12489, Berlin, Germany., Sánchez-Barriga J; Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Strasse 15, 12489, Berlin, Germany. jaime.sanchez-barriga@helmholtz-berlin.de.
Jazyk:	angličtina
Zdroj:	Nature communications [Nat Commun] 2017 Oct 17; Vol. 8 (1), pp. 968. Date of Electronic Publication: 2017 Oct 17.
DOI:	10.1038/s41467-017-01204-0
Abstrakt:	Topological insulators constitute a new phase of matter protected by symmetries. Time-reversal symmetry protects strong topological insulators of the Z 2 class, which possess an odd number of metallic surface states with dispersion of a Dirac cone. Topological crystalline insulators are merely protected by individual crystal symmetries and exist for an even number of Dirac cones. Here, we demonstrate that Bi-doping of Pb 1-x Sn x Se (111) epilayers induces a quantum phase transition from a topological crystalline insulator to a Z 2 topological insulator. This occurs because Bi-doping lifts the fourfold valley degeneracy and induces a gap at [Formula: see text], while the three Dirac cones at the [Formula: see text] points of the surface Brillouin zone remain intact. We interpret this new phase transition as caused by a lattice distortion. Our findings extend the topological phase diagram enormously and make strong topological insulators switchable by distortions or electric fields.Transitions between topological phases of matter protected by different symmetries remain rare. Here, Mandal et al. report a quantum phase transition from a topological crystalline insulator to a Z 2 topological insulator by doping Bi into Pb 1-x Sn x Se (111) thin films.
Databáze:	MEDLINE
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