Sommaire:

Pb1-xSnxSe (x>0.16) topological crystalline insulators host massless surface Dirac cones stemming from a band inversion that occurs at the mirror symmetric L-points of the Brillouin zone [1], [2]. In this talk, I will present two experimental observables related to the emergence of the topological phase in Pb1-xSnxSe. First, I will show how bulk transport is uniquely altered by the band inversion, and exhibits a negative magnetoresistance when the system is in the quantum limit [3]. Second, I will demonstrate the emergence of topological interface states at a topological-trivial junction formed between Pb0.75Sn0.25Se and Pb1-yEuySe. Using infrared Landau level spectroscopy, I will present our results evidencing the robustly Dirac-like nature of these surface states up to 15T, and their mass acquisition and suppression as a function of increasing temperature and quantum confinement [4]. Overall, I will argue throughout my talk that Pb1-xSnxSe is – truly – a model system to study topological phase of matter.
[1] T. Hsieh et al. Nature Comm. 3 982 (2012)
[2] B.A. Assaf, T. Phuphachong et al. npj Quantum Materials 2 26 (2017)
[3] B.A. Assaf, T. Phuphachong et al. Phys. Rev. Lett. 119 106602 (2017)
[4] G. Krizman, B.A. Assaf et al. in preparation

Pour plus d'informations, merci de contacter Teppe F.