Pressure driven quantum critical point and f-electron delocalization in CeNiAsO

Zhu’an Xu

Department of Physics, Zhejiang University, Hangzhou 310027, China


    We investigated both hydrostatic pressure and chemical pressure (i.e. P-for-As doping) effect on CeNiAsO, an antiferromagnetic dense Kondo lattice. It is found that magnetic ordering of Ce ions is continuously suppressed with increasing pressure, leading to a paramagnetic metal phase above a pressure of 6.5 kbar. Non-Fermi-liquid behavior is observed at this point, accompanied by a "divergent" A coefficient in resistivity and a sign change in the Hall coefficient. Similar phenomena under the chemical pressure are also observed in the P-doped CeNiAs1-xPxO system with the critical doping level xc = 0.4. Ce-4f electron is proposed to delocalize at the quantum critical point (QCP), consistent with the first-principle calculation which also manifests rapidly increased Kondo scale TK with chemical pressure. All these findings reveal CeNiAsO is a new example of Kondo breakdown type of pressure driven QCP.