Dresden 2020 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 65: Nanomaterials - II

MM 65.2: Talk

Thursday, March 19, 2020, 17:45–18:00, IFW D

Epitaxial NbP and TaP Weyl Semimetal thin films - a new playground for topological heterostructures — •Amilcar Bedoya Pinto, Avanindra Kumar Pandeya, Defa Liu, Hakan Deniz, Kai Chang, Hengxin Tan, Hyeon Han, Jagannath Jena, Ilya Kostanovskiy, and Stuart Parkin — Max Planck-Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany

Weyl Semimetals (WSMs), a recently discovered topological state of matter, exhibit an electronic structure governed by linear band dispersions and degeneracy (Weyl) points leading to rich physical phenomena, which are yet to be exploited in thin film devices. While WSMs were established in the monopnictide compound family several years ago, the growth of thin films has remained a challenge. Here, we report the growth of epitaxial thin films of NbP and TaP by means of molecular beam epitaxy. Single crystalline films are grown on MgO (001) substrates using thin Nb (Ta) buffer layers, and are found to be tensile strained (1%) and with slightly P-rich stoichiometry with respect to the bulk crystals. The resulting electronic structure exhibits topological surface states characteristic of a P-terminated surface and linear dispersion bands featuring a Fermi-level shift of -0.2 eV with respect to the Weyl points. The growth of epitaxial thin films allows the use of strain and controlled doping to tune the electronic structure of Weyl Semimetals on demand, paving the way for the rational design and fabrication of electronic devices ruled by topology.