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TT: Fachverband Tiefe Temperaturen
TT 51: Correlated Electrons: Charge Order
TT 51.5: Talk
Thursday, March 30, 2023, 16:15–16:30, HSZ 103
Lattice instability in charge-frustrated CsW2O6 — •Pascal Reiss1, Peter Wochner1, Armin Schulz1, Jürgen Nuss1, Masahiko Isobe1, and Hidenori Takagi1,2,3 — 1Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany — 2Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Germany — 3Department of Physics, The University of Tokyo, Bunkyo, Tokyo, Japan
The transition metal compound CsW2O6 represents an intriguing example of a pyrochlore structure at quarter filling. Starting from a bad metal with a nominal W5.5+ oxidation state, the system suffers a metal-to-insulator transition around Tc ≈ 215 K. Here, a breathing distortion leads to the formation of regular molecular W3 trimers with 2 localised electrons each, and a remaining W6+ site devoid of 5d electrons [1]. However, the origin of the transition as well as the electronic nature of the low-temperature phase remain unclear [2].
To elucidate the origin of the 215 K transition, we will present our recent structural investigations and transport measurements on CsW2O6 conducted under high pressures, where we uncover another structural instability, distinct from the ambient pressure one.
[1] Y. Okamoto et al., Nat. Commun. 11 (2020)
[2] N. Nakai and C. Hotta, Nat. Commun. 13 (2022)