Synthesis, Structural, and Transport Properties of Cr-doped BaTi_2As_2O

TL;DR

This study investigates how Cr doping affects the charge density wave transition in BaTi_2As_2O, revealing suppression of CDW transition without inducing superconductivity, supported by experimental and first-principles calculations.

Contribution

It provides a systematic analysis of Cr doping effects on BaTi_2As_2O's properties, highlighting the suppression of CDW transition and offering insights into related layered superconducting materials.

Findings

Cr doping gradually suppresses the CDW transition temperature.

No superconductivity observed down to 2 K despite doping.

First-principles calculations support experimental results.

Abstract

The interplay between unconventional superconductivity and the ordering of charge/spin density wave is one of the most vital issues in both condensed matter physics and material science. The Ti-based compound BaTi_2As_2O, which can be seen as the parent phase of superconducting BaTi_2Sb_2O, has a layered structure with a space group P4/mmm, similar to that of cuprate and iron-based superconductors. This material exhibits a charge density wave (CDW) ordering transition revealed by an anomaly at around 200 K in transport measurements. Here, we report the synthesis and systematical study of the physical properties in Cr-doped BaTi_{2-x}Cr_xAs_2O (x = 0 - 0.154), and demonstrate that the transition temperature of the CDW ordering is suppressed gradually by the doped Cr element. The magnetization measurements confirm the evolution of the CDW ordering transition. These observed behaviors are similar to that observed in iron-based superconductors, but no superconductivity emerges down to 2 K. In addition, the first-principles calculations are also carried out for well-understanding the nature of experimental observations.