Superconductivity in chromium nitrides Pr3Cr10-xN11 with strong electron correlations

Abstract

Exploration of superconductivity in Cr-based compounds has attracted considerable interest because only a few Cr-based superconductors (CrAs, A2Cr3As3 and ACr3As3 (A = K, Rb, Cs, Na)) have been discovered so far and they show an unconventional pairing mechanism. We report the discovery of bulk superconductivity at 5.25 K in chromium nitride in Pr3Cr10-xN11 with a cubic lattice structure. A relatively large upper critical field of Hc2(0) ∼ 12.6 T is determined, which is larger than the estimated Pauli-paramagnetic pair-breaking magnetic field. The material has a large electronic specific-heat coefficient of 170 mJ K−2 mol−1—about 10 times larger than that estimated by the electronic structure calculation, which suggests that correlations between 3d electrons are very strong in Pr3Cr10-xN11, and thus quantum fluctuations might be involved. Electronic structure calculations show that the density of states at the Fermi energy are contributed predominantly by Cr 3d electrons, implying that the superconductivity results mainly from the condensation of Cr 3d electrons. Pr3Cr10-xN11 represents a rare example of possible unconventional superconductivity emerging in a 3D system with strong electron correlations. Nevertheless, clarification of the specific pairing symmetry needs more investigation.

The chromium pnictide materials: A tunable platform for exploring new exciting phenomena

“…This belief has been very recently corroborated by the discovery of bulk superconductivity in chromium nitrides La 3 Cr 10−x N 11 [64] and Pr 3 Cr 10−x N 11 [65]. Although these materials do not belong to As-chromium pnictides, they are new N-pnictides that share with the materials here discussed predominantly 3d electrons at Fermi level, implying that the superconductivity mainly results from the condensation of these electrons.…”

X-Ray and Morphological Analysis of InAs-CrAs Eutectic Nanocomposite Systems

“…According to the results of these studies, the connection between the ferromagnetic constituents perpendicular to the crystallization axis in the CrAs junction is antiferromagnetic. Consequently consideration of the InAs-CrAs systems is of substantial interestl [4][5][6][7]. The present paper is devoted to synthesis and structure investigated of InAs-CrAs systems.…”

Dimensionality of the Superconductivity in the Transition Metal Pnictide WP

“…Although many interesting studies have been so far reported on these and other similar compounds, both theoretical [12][13][14][15][16][17][18][19][20][21][22][23][24][25] and experimental [26][27][28][29][30][31][32][33][34][35][36], only a limited amount of information on WP single crystal system is until now available [8]. The aim of this paper is to give a contribution to the investigation of the properties of WP compound, providing electronic structure calculations and a consistent description of resistivity measurements from experiments carried out on WP single crystal samples.…”