Absence of precursor incommensurate charge order in electronic nematic Ba0.35Sr0.65Ni2As2

TL;DR

This study investigates the absence of incommensurate charge order in Ba0.35Sr0.65Ni2As2, revealing that charge and nematic orders vanish at this composition, contrasting previous findings in related compounds.

Contribution

The paper provides experimental evidence that incommensurate charge order disappears at a specific Sr substitution level in Ba1-xSrxNi2As2, clarifying the relationship between charge and nematic orders in this system.

Findings

Incommensurate charge order vanishes at x=0.65.

Nematic order is closely tied to charge order in the tetragonal state.

Charge order evolves from incommensurate to commensurate before vanishing.

Abstract

Recent discoveries of charge order and electronic nematic order in the iron-based superconductors and cuprates have pointed towards the possibility of nematic and charge fluctuations playing a role in the enhancement of superconductivity. The Ba1-xSrxNi2As2 system, closely related in structure to the BaFe2As2 system, has recently been shown to exhibit both types of ordering without the presence of any magnetic order. We report single crystal X-ray diffraction, resistance transport measurements, and magnetization of \BaSrLate, providing evidence that the previously reported incommensurate charge order with wavevector $(0,0.28,0)_{tet}$ in the tetragonal state of \BaNi~vanishes by this concentration of Sr substitution together with nematic order. Our measurements suggest that the nematic and incommensurate charge orders are closely tied in the tetragonal state, and show that the $(0,0.33,0)_{tri}$ charge ordering in the triclinic phase of BaNi2As2 evolves to become $(0,0.5,0)_{tri}$ charge ordering at $x$=0.65 before vanishing at $x$=0.71.