Dresden 2017 – wissenschaftliches Programm
DS 33.5: Vortrag
Mittwoch, 22. März 2017, 16:00–16:15, HSZ 204
Emergent Weyl fermion bulk excitations in TaP evidenced from 181Ta quadrupole resonance — H. Yasuoka1,2, T. Kubo1,3, Y. Kishimoto1,3, D. Kasinathan1, M. Schmidt1, B. Yan1, Y. Zhang4, H. Tou3, C. Felser1, A.P. Mackenzie1,5, and •M. Baenitz1 — 1MPI for Chemical Physics of Solids, 01187 Dresden, Germany — 2Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Japan — 3Department of Physics, Graduate school of Science, Kobe University, Kobe, Japan — 4IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany — 5SUPA, School of Physics & Astronomy, University of St. Andrews, UK
The monophosphite TaP has a non centrosymmetric structure and sizable spin orbit coupling and belongs the class of Weyl semimetals. A crossing of lineare dispersive (E ∝ k) topologically protected polarized bands in a single point in reciprocal space defines the Weyl node where the fermion mass vanishes theoretically and a giant orbital hyperfine coupling is expected . 181Ta quadrupole resonance (NQR) resolves three NQR lines associated to the split level transitions for I=7/2 Ta. The spin lattice relaxation was measured for the ±5/2 ↔ ±3/2 transition. Above 30 K, a pronounced (1/T1T) ∝ T2 is found. We attributed this to the magnetic excitations of Weyl fermions (N(E) ∝ E2) with temperature dependent orbital hyperfine coupling in agreement with the prediction from theory .
 Z. Okvatovity et al., arXiv:1609.3370v1