Epitaxial growth of hexagonal tungsten bronze CsxWO3 films in superconducting phase region exceeding bulk limit

摘要

We report epitaxial synthesis of superconducting CsxWO3 (x = 0.11, 0.20,0.31) films on Y-stabilized ZrO2 (111) substrates. The hexagonal crystalstructure was verified not only for composition within the stable region ofbulk (x = 0.20, 0.31), but also for the out-of-range composition (x = 0.11).The onset of superconducting transition temperature (TC) was recorded 5.8 K forx = 0.11. We found strong correlation between TC and c-axis length,irrespective of the Cs content. The results indicate that hiddensuperconducting phase region of hexagonal tungsten bronze is accessible byusing epitaxial synthesis of lightly doped films.