Indexed by:Journal paper First Author:J-Z Ma Correspondence Author:Ming Shi Co-author:CJ Yi,Hong Ding,Tian Qian,YG Shi,Markus Müller,Christopher Mudry,Cesare Franchini,Michele Reticcioli,Joël Mesot,Wulf Wulfhekel,G Xu,Y-M Xiong,M Song,Marisa Medarde,SM Nie,Vladimir N Strocov,Alla Chikina,Yan Sun,LQ Yan,Muntaser Naamneh,Meng-Yu Yao,Tian Shang,Jasmin Jandke Journal:Science advances Included Journals:SCI Discipline:Science First-Level Discipline:Physics Document Type:J Volume:5 Issue:7 Page Number:eaaw4718 ISSN No.:2375-2548 Date of Publication:2019-07-12 Impact Factor:13.117 Abstract:Weyl fermions as emergent quasiparticles can arise in Weyl semimetals (WSMs) in which the energy bands are nondegenerate, resulting from inversion or time-reversal symmetry breaking. Nevertheless, experimental evidence for magnetically induced WSMs is scarce. Here, using photoemission spectroscopy, we observe that the degeneracy of Bloch bands is already lifted in the paramagnetic phase of EuCd2As2. We attribute this effect to the itinerant electrons experiencing quasi-static and quasi–long-range ferromagnetic fluctuations. Moreover, the spin-nondegenerate band structure harbors a pair of ideal Weyl nodes near the Fermi level. Hence, we show that long-range magnetic order and the spontaneous breaking of time-reversal symmetry are not essential requirements for WSM states in centrosymmetric systems and that WSM states can emerge in a wider range of condensed matter systems than previously thought.