XXXVI Reunión Bienal de la Real Sociedad Española de Física

High magnetic field Scanning Tunneling Microscopy and Spectroscopy in the type-II Weyl semimetal WTe2

Not scheduled

Aula Magna (Santiago de Compostela, Facultade de Química)

Description

The material WTe2 crystallizes in a layered structure without inversion symmetry. The crystals are of extremely high quality. In particular, at zero field, the residual resistance is nearly three orders of magnitude smaller than the room temperature resistance [1]. Interestingly, when applying a magnetic field, the magnetoresistance increases by more than five orders of magnitude [1]. The dependence on the magnetic field is linear and the origin for this linear magnetoresistance is highly debated. The Fermi surface has been studied using ARPES and quantum oscillations [2]. This material is conjectured to be a type-II Weyl semimetal. Here we use Scanning Tunneling Spectroscopy at high magnetic fields to investigate the electronic structure at the surface down to atomic scale. We observe atomic scale images showing the crystalline structure without inversion symmetry. We make quasiparticle interference imaging and find topologically non-trivial features in the bandstructure. Finally, we also discuss a new shapal-made, very small-sized, high magnetic field STM (which is a modified design of [3]) that will be capable to perform measurements down to 10 mK and up to 17 T. [1] Y. Wu et al., Phys. Rev. Lett. 115, 166602 (2015) [2] Y. Wu et al., Phys. Rev. B., 94, 121113 (2016) [3] H. Suderow et al. Review of Scientific Instruments 82, 033711 (2011)