%0 Journal Article %1 PhysRevB.109.035145 %A Knoll, Andy %A Timm, Carsten %D 2024 %I American Physical Society %J Phys. Rev. B %K a %N 3 %P 035145 %R 10.1103/PhysRevB.109.035145 %T Irreducible momentum-space spin structure of Weyl semimetals and its signatures in Friedel oscillations %U https://link.aps.org/doi/10.1103/PhysRevB.109.035145 %V 109 %X Materials that break time-reversal or inversion symmetry possess nondegenerate electronic bands, which can touch at so-called Weyl points. The spinor eigenstates in the vicinity of a Weyl point exhibit a well-defined chirality ±1. Numerous works have studied the consequences of this chirality, for example, in unconventional magnetoelectric transport. However, even a Weyl point with isotropic dispersion is not only characterized by its chirality but also by the momentum dependence of the spinor eigenstates. For a single Weyl point, this momentum-space spin structure can be brought into standard “hedgehog” form by a unitary transformation, but for two or more Weyl points, this is not possible. In this work, we show that the relative spin structure of a pair of Weyl points has strong qualitative signatures in the electromagnetic response. Specifically, we investigate the Friedel oscillations in the induced charge density due to a test charge for a centrosymmetric system consisting of two Weyl points with isotropic dispersion. The most pronounced signature is that the amplitude of the Friedel oscillations falls off as 1/r4 in directions in which both Weyl points exhibit the same spin structure, while for directions with inverted spin structures, the amplitude of the Friedel oscillations decreases as 1/r3.

@article{PhysRevB.109.035145, abstract = {Materials that break time-reversal or inversion symmetry possess nondegenerate electronic bands, which can touch at so-called Weyl points. The spinor eigenstates in the vicinity of a Weyl point exhibit a well-defined chirality ±1. Numerous works have studied the consequences of this chirality, for example, in unconventional magnetoelectric transport. However, even a Weyl point with isotropic dispersion is not only characterized by its chirality but also by the momentum dependence of the spinor eigenstates. For a single Weyl point, this momentum-space spin structure can be brought into standard “hedgehog” form by a unitary transformation, but for two or more Weyl points, this is not possible. In this work, we show that the relative spin structure of a pair of Weyl points has strong qualitative signatures in the electromagnetic response. Specifically, we investigate the Friedel oscillations in the induced charge density due to a test charge for a centrosymmetric system consisting of two Weyl points with isotropic dispersion. The most pronounced signature is that the amplitude of the Friedel oscillations falls off as 1/r4 in directions in which both Weyl points exhibit the same spin structure, while for directions with inverted spin structures, the amplitude of the Friedel oscillations decreases as 1/r3.}, added-at = {2024-04-26T15:37:24.000+0200}, author = {Knoll, Andy and Timm, Carsten}, biburl = {https://www.bibsonomy.org/bibtex/2097a9bd66e6fc2f59705094692b27291/ctqmat}, day = 19, doi = {10.1103/PhysRevB.109.035145}, interhash = {cd257be0666ff247c39910821c58c2c6}, intrahash = {097a9bd66e6fc2f59705094692b27291}, journal = {Phys. Rev. B}, keywords = {a}, month = {01}, number = 3, numpages = {18}, pages = 035145, publisher = {American Physical Society}, timestamp = {2024-04-26T15:37:24.000+0200}, title = {Irreducible momentum-space spin structure of Weyl semimetals and its signatures in Friedel oscillations}, url = {https://link.aps.org/doi/10.1103/PhysRevB.109.035145}, volume = 109, year = 2024 }