paper

Orbital Ordering in the Charge Density Wave Phases of BaNi $_{2}$ (As $_{1 - x}$ P $_{x}$ ) $_{2}$

arXiv:2509.05200 · doi:10.1103/x5bv-w84m

Abstract

We use resonant X-ray scattering at the nickel L $_{2, 3}$ edges to investigate the interplay between orbital degrees of freedom and charge density waves (CDW) in the superconductor BaNi $_{2}$ (As $_{1 - x}$ P $_{x}$ ) $_{2}$ . Both the incommensurate and commensurate CDWs in this system exhibit strong resonant enhancement with distinct energy and polarization dependencies, indicative of orbital ordering. Azimuthal-angle-dependent measurements reveal a lowering of the local Ni site symmetry, consistent with monoclinic or lower point group symmetry. The scattering signatures of both CDWs are dominated by contributions from Ni $d_{x z, y z}$ orbitals, with similar orbital character despite their distinct wave vectors. These findings point to a shared orbital-driven formation mechanism and provide new insight into the symmetry breaking and orbital/nematic fluctuations in the high-temperature regime of the superconductor BaNi $_{2}$ (As $_{1 - x}$ P $_{x}$ ) $_{2}$ .

8 pages, 3 figures, published version

Orbital Ordering in the Charge Density Wave Phases of BaNi2​(As1−x​Px​)2​

Abstract

Orbital Ordering in the Charge Density Wave Phases of BaNi $_{2}$ (As $_{1 - x}$ P $_{x}$ ) $_{2}$