Regensburg 2016 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 24: Transport: Weyl Semimetals
TT 24.8: Talk
Tuesday, March 8, 2016, 11:45–12:00, H18
Magnetic resonance as a local probe for linear bands in the Weyl semimetals NbP and TaP — •Michael Baenitz, Hiroshi Yasuoka, Mayukh Majumder, Chandra Shekhar, Binghai Yan, Claudia Felser, and Markus Schmidt — MPI for Chemical Physics of Solids, 01187 Dresden, Germany
Some compensated d-electron semimetals, for example the monophosphites NbP and TaP, with non centrosymmetric structure and with sizable spin orbit coupling (SOC) form a new class of material: the Weyl semimetals (WSM). A unique linear crossing of valence- and conduction- band in a single point in reciprocal space defines the so called Weyl point where the fermion mass vanishes theoretically. In real materials the Fermi level EF does not exactly match the Weyl node and as a consequence residual very light fermions are found. Due to the SOC these Weyl fermions have a chirality (handedness) on their linear dispersive (E ∝ k) bands and frequently a linear density of states (DOS) at the Fermi level EF. We use NMR as a probe for this linear d- electron bands. The shift provides the s- and d- electron contributions to the DOS at EF, whereas the spin lattice relaxation is governed by low energy excitations around EF. 31P (I = 1/2) - Fourier - transform - and 95Nb (I = 9/2) - broadline - sweep - NMR studies are performed. We investigated powder samples as well as single crystals on both systems. The angular dependence of the 95Nb- and 31P - NMR lines is discussed.