[20p-B204-1~13] 6.3 Oxide electronics

▼ [20p-B204-9] AMoO₂ (A = Li, Na, K): Two-dimensional Mott insulators with tunable MoO₂ interlayer distance

〇(D)Shuxin Zhang¹, Takuto Soma¹, Akira Ohtomo¹ (1.Tokyo Tech.)

Keywords:epitaxial film, Mott insulator, interlayer distance

The ternary molybdenum bronzes A_xMo_yO_z, where A is alkali metals, have been enthusiastically studied for their low-dimensional crystal and band structures associated with rich physical properties. Much attention has been paid to ″blue bronzes″ A_0.3MoO₃ (4d^0.3) with metal-to-insulator transition driven by charge density wave, ″purple bronzes″ A_0.6Mo₉O₁₇ (4d^0.48) with spin-triplet superconductivity, and K_0.05MoO_1.63 (4d^2.79) with superconductivity observed around T_c = 6.5 K. However, there has been few reports on fabrication of ternary A_xMo_yO_z films due to difficulty in obtaining the specific stoichiometric phases. In this study, we focus on the epitaxial growth of layered rock-salt-type AMoO₂ (A = Li, Na, K). AMoO₂ has ideal two-dimensional (2D) MoO₂ layers in their crystal structure and shows Mott insulating properties with the valence state of Mo³⁺ (4d³), implying the emergence of exotic electronic states in 2D MoO₂ layers with carrier control.