10.3390/condmat5020032 Polaronic States and Superconductivity in WO_3-x Salje Dr. Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK Ekhard@esc.cam.ac.uk 01 05 2020 5 2 27 04 2020 e32 Superconducting domain boundaries were found in WO_3-x and doped WO₃. The charge carriers in WO₃-type materials were identified by Schirmer and Salje as bipolarons. Several previous attempts to determine the electronic properties of polarons in WO₃ failed until Bousque et al. (2020) reported a full first principle calculation of free polarons in WO₃. They confirmed the model of Schirmer and Salje that each single polaron is centred around one tungsten position with surplus charges smeared over the adjacent eight tungsten positions. Small additional charges are distributed further apart. Further calculations to clarify the coupling mechanism between polaron to form bipolarons are not yet available. These calculations would help to identify the carrier distribution in Magneli clusters, which were shown recently to contain high carrier concentrations and may indicate totally localized superconductivity in non-percolating clusters. Engineering and Physical Sciences Research Council EP/P024904/1 © 1996-2020 MDPI (Basel, Switzerland) 2020 This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited ferroelastic WO3 polarons polaronic superconductivity Condensed Matter Condens Matter 2410-3896 MDPI