We show that the valence electrons of Ba3NaRu2O9, which has a quasimolecular structure, completely crystallize below 210 K. Using an extended Hubbard model, we show that the charge ordering instability results from long-range Coulomb interactions. However, orbital ordering, metal-metal bonding, and formation of a partial spin gap enforce the magnitude of the charge separation. The striped charge order and frustrated hcp lattice of Ru2O9 dimers lead to competition with a quasidegenerate charge-melted phase under photoexcitation at low temperature. Our results establish a broad class of simple metal oxides as models for emergent phenomena at the border between the molecular and solid states.
T. A. Bird, A. Herlihy and Mark S. Senn, J. Appl. Cryst. (2021). 54. A novel symmetry-adapted pair distribution function analysis (SAPA) method for extracting information on local distortions from pair distribution function data isRead more
Gabriel Clarke, Chris Ablitt, John Daniels, Stefano Checchia and Mark S. Senn. J. Appl. Cryst. (2021) 54. Improper ferroelectric materials are increasingly under investigation for their potential to expand the catalogue of functional ferroelectrics andRead more
Fernando Pomiro, Chris Ablitt, Nicholas C. Bristowe, Arash A. Mostofi, Choongjae Won, Sang-Wook Cheong, and Mark S. Senn.Phys. Rev. B 102, 014101. Hybrid improper ferroelectrics (HIFs) have been studied intensively over the past few yearsRead more
Tobias Bird, Jessica Woodland-Scott, Lei Hu, Michael Wharmby, Jun Chen, Andrew Goodwin, Mark Senn, Phys. Rev. B 101(2020), 064306. We use a symmetry-motivated approach to analysing X-ray pair distribution functions to study the mechanism ofRead more
Chris Ablitt, Harriet McCay, Sarah Craddock, Lauren Cooper, Emily Reynolds, Arash A. Mostofi, Nicholas C. Bristowe, Claire A. Murray, and Mark S. Senn. Chem. Mater. 2020, 32, 1, 605-610. By tuning the tolerance factor, t,Read more