Pressure-induced superconductivity in CeNiGe3

Superconducting phase transition in Y NiGe3, a non--electron reference to the unconventional superconductor CeNiGe3

“…The compound YNiGe 3 was found to exhibit an ambient-pressure superconductivity below T c = 0.46 K, which is close to the maximal T c evidenced in CeNiGe 3 around the quantum critical point. [3,4,5,6] In this context it is worth noting that substitution of Ce by Y results in 6%-reduction of the unit cell volume of the system, which can be roughly considered as equivalent to high hydrostatic pressure. Therefore, the finding of the superconductivity in YNiGe 3 , which does not contain f -electrons, may shed new light on the character of the superconductivity in the isostructural CeNiGe 3 compound.…”

“…[3,4] More detailed investigations of the compound showed that the superconductivity emerges in CeNiGe 3 not only in the critical region, but also deeply in the antiferromagnetically ordered phase, forming two distinct superconducting domes on the P − T phase diagram, located around P max and P c . [5,6] Nuclear quadrupole resonance (NQR) measurements revealed that the onset of the superconductivity is in both domes a consequence of the presence of the 4f electrons of cerium. [7,8,9] YNiGe 3 was used in our previous studies as an isostructural non-magnetic counterpart to CeNiGe 3 .…”

The electronic structure of CeNiGe3 and YNiGe3 superconductors by ab initio calculations

“…It is known that the phenomenon of pressure-induced SC in such f-electron systems occurs around the quantum critical point (QCP), where their antiferromagnetic (AFM) order vanishes and the heavy-fermion (HF) state is formed. Meanwhile, in CeNiGe 3 , an SC mechanism is more complex, since its SC is robust not only in the HF state (with strong spin fluctuations) at QCP for critical pressure of 6-7 GPa, but in a much wider pressure range (1.7 -9.3 GPa), where it is able also to coexist with an ordered AFM state [6,7,8].…”