Moving Dirac nodes by chemical substitution
Résumé
Dirac fermions play a central role in the study of topological phases, for they can generate a variety of exotic states, such as Weyl semimetals and topological insulators. The control and manipulation of Dirac fermions constitute a fundamental step toward the realization of novel concepts of electronic devices and quantum computation. By means of Angle-Resolved Photo-Emission Spectroscopy (ARPES) experiments and ab initio simulations, here, we show that Dirac states can be effectively tuned by doping a transition metal sulfide, B a N i S 2 , through Co/Ni substitution. The symmetry and chemical characteristics of this material, combined with the modification of the charge-transfer gap of B a C o 1 − x N i x S 2 across its phase diagram, lead to the formation of Dirac lines, whose position in k-space can be displaced along the Γ − M symmetry direction and their form reshaped. Not only does the doping x tailor the location and shape of the Dirac bands, but it also controls the metal-insulator transition in the same compound, making B a C o 1 − x N i x S 2 a model system to functionalize Dirac materials by varying the strength of electron correlations.
Domaines
Physique [physics]| Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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