$$\textit{J}$$ = 0 nonmagnetic insulating state in K₂OsX₆ ($$\textit{X}$$ = F, Cl, and Br)

Journal Article · Wed Oct 26 00:00:00 EDT 2022 · Physical Review. B

DOI:https://doi.org/10.1103/physrevb.106.155148· OSTI ID:1895206

Zhang, Yang ^[1]; Lin, Ling-Fang ^[1]; Moreo, Adriana ^[2]; Dagotto, Elbio ^[2]

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1. Univ. of Tennessee, Knoxville, TN (United States)
2. Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

In 4$$\textit{d}$$ /5$$\textit{d}$$ transition-metal systems, many interesting physical properties arise from the interplay of bandwidth, electronic correlations, and spin-orbit interactions. Here, using ab initio density functional theory, we systematically study the double-perovskite-like system K₂OsX6 ($$\textit{X}$$ = F, Cl, and Br) with a $5d^4$ electronic configuration. In this work, our main result is that the $$\textit{J}$$ = 0 nonmagnetic insulating state develops in this system, induced by strong spin-orbit coupling (SOC). Specifically, the well-separated OsX₆ octahedra lead to the cubic crystal-field limit and result in dramatically decreasing hoppings among nearest neighbor Os-Os sites. In this case, the three degenerate $$t_{2g}$$ orbitals are reconstructed into two “effective” $$j_{\text{eff}}$$ ($$j_{\text{eff}}$$ = 1/2 and $$j_{\text{eff}}$$ = 3/2 states) states separated by the strong SOC, opening a gap with four electrons occupying the$$j_{\text{eff}}$$ = 3/2 orbitals. Furthermore, the hybridization between the Os 5$$\textit{d}$$ orbitals and the $$\textit{X}$$ ($$\textit{X}$$ = F, Cl, and Br) $$\textit{p}$$ orbitals increases from F to Br, leading the electrons in K₂OsF₆ to be more localized than in K₂OsCl₆ and K₂OsBr₆, resulting in a smaller bandwidth for K₂OsF₆ than in the Cl- or Br-cases. Our results provide guidance to experimentalists and theorists working on this interesting family of osmium halides.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1895206
• Journal Information: Physical Review. B, Journal Name: Physical Review. B Journal Issue: 15 Vol. 106; ISSN 2469-9950
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY