Luo, YongkangPourovskii, LeonidRowley, S.E.Li, YukeFeng, ChunmuGeorges, AntoineDai, JianhuiCao, GuanghanXu, ZhuﾒanSi, QimiaoOng, N.P.2015-07-082015-07-082014Luo, Yongkang, Pourovskii, Leonid, Rowley, S.E., et al.. "Heavy-fermion quantum criticality and destruction of the Kondo effect in a nickelﾠoxypnictide." <i>Nature Materials,</i> 13, (2014) Nature Publishing Group: 777-781. http://dx.doi.org/10.1038/nmat3991.https://hdl.handle.net/1911/80847A quantum critical point arises at a continuous transformation between distinct phases of matter at zero temperature. Studies in antiferromagnetic heavy-fermion materials have revealed that quantum criticality has several classes, with an unconventional type that involves a critical destruction of the Kondo entanglement [1,2]. To understand such varieties, it is important to extend the materials basis beyond the usual setting of intermetallic compounds. Here we show that a nickel oxypnictide, CeNiAsO, exhibits a heavy-fermion antiferromagnetic quantum critical point as a function of either pressure or P/As substitution. At the quantum critical point, non-Fermi-liquid behaviour appears, which is accompanied by a divergent effective carrier mass. Across the quantum critical point, the low-temperature Hall coefficient undergoes a rapid sign change, suggesting a sudden jump of the Fermi surface and a destruction of the Kondo effect [3,4]. Our results imply that the enormous materials basis for the oxypnictides, which has been so crucial in the search for high-temperature superconductivity, will also play a vital role in the effort to establish the universality classes of quantum criticality in strongly correlated electron systems.engThis is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is the Nature Publishing Group.Journal articlehttp://dx.doi.org/10.1038/nmat3991