Impurity scattering in Weyl semimetals and their stability classification
2013 (English)In: New Journal of Physics, ISSN 1367-2630, Vol. 15, art.nr.-123019 p.Article in journal (Refereed) Published
Weyl semimetals (WS) are a new class of Dirac-type materials exhibiting a phase with bulk energy nodes and an associated vanishing density of states (DOS). We investigate the stability of this nodal DOS suppression in the presence of local impurities and consider whether or not such a suppression can be lifted by impurity-induced resonances. We find that while a scalar (chemical potential type) impurity can always induce a resonance at arbitrary energy and hence lift the DOS suppression at Dirac/Weyl nodes, for many other impurity types (e.g. magnetic or orbital mixing), resonances are forbidden in a wide range of energy. We investigate a four-band tight-binding model of WS adapted from a physical heterostructure construction due to Burkov et al (2011 Phys. Rev. B 84 235126), and represent a local impurity potential by a strength g as well as a matrix structure Lambda. A general framework is developed to analyze this resonance dichotomy and make connection with the phase shift picture in scattering theory, as well as to determine the relation between resonance energy and impurity strength g. A complete classification of impurities based on Lambda, based on their effect on nodal DOS suppression, is tabulated. We also discuss the differences between continuum and lattice approaches.
Place, publisher, year, edition, pages
2013. Vol. 15, art.nr.-123019 p.
IdentifiersURN: urn:nbn:se:su:diva-100391DOI: 10.1088/1367-2630/15/12/123019ISI: 000329438400003OAI: oai:DiVA.org:su-100391DiVA: diva2:693370
NSF DMR-1007028; US DoE Basic Energy Sciences; Center for Integrated Nanotechnologies; US Department of Energy DE-AC52-06NA25396; ERC-DM321031; VR-621-2012-298.2014-02-042014-02-032014-02-04Bibliographically approved