Bandwidth dependence of insulator-metal transitions in perovskite cobalt oxides.
Bandwidth dependence of insulator-metal transitions in perovskite cobalt oxides.
复制标题
钙钛矿钴氧化物中绝缘体-金属转变的带宽依赖性。
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
Tokura
中科院分区：
文献类型：
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作者：
Yamaguchi;Okimoto;Tokura
研究了钙钛矿型钴氧化物$R\mathrm{Co}{\mathrm{O}}_{3}(R=\mathrm{L}\mathrm{a}、\phantom{\rule{0ex}{0ex}}\mathrm{P}}\mathrm{N}\mathrm{d}、\phantom{\rule{0ex}{0ex}}\mathrm{S}}、\phantom{\rule{0ex}{0ex}}\mathrm{E}}、\phantom{\rule{0ex}{0ex}}\mathrm{N}}、\phantom{\rule{0ex}{0ex}}\mathrm{N}}、\phantom{\rule{0ex}{0ex}}\mathrm{N}}、\phantom{\rule{0ex}{0ex}}\mathrm{d}、\phantom{\rule{0ex}{0ex}}\mathrm{G}\mathrm{d})$的绝缘体-金属跃迁和相关电子结构单电子带宽变化（$W$）。所有化合物都表现出绝缘基态，但在500-700 K时经历逐渐的绝缘体-金属（$I\ensuremath{-}M$）转变。系统地观察了I\ensuremath{-}M$转变温度（${T}_{\ mathm {IM}}$）以及绝缘相的热电荷和光电荷间隙随R$物质（或等价的W$）的变化。与每个$R\ mathm {Co}{\ mathm {O}}_{3}$中的电荷隙相比，${T}_{\ mathm {IM}}$的电荷隙异常低，这表明$I\ensuremath{-}M$跃迁应被视为热诱导的莫特跃迁。
Insulator-metal transitions and related electronic structures have been investigated for single crystals of perovskite-type cobalt oxides $R\mathrm{Co}{\mathrm{O}}_{3}(R=\mathrm{L}\mathrm{a},\phantom{\rule{0ex}{0ex}}\mathrm{P}\mathrm{r},\phantom{\rule{0ex}{0ex}}\mathrm{N}\mathrm{d},\phantom{\rule{0ex}{0ex}}\mathrm{S}\mathrm{m},\phantom{\rule{0ex}{0ex}}\mathrm{E}\mathrm{u},\phantom{\rule{0ex}{0ex}}\mathrm{a}\mathrm{n}\mathrm{d}\phantom{\rule{0ex}{0ex}}\mathrm{G}\mathrm{d})$ with $R$-dependent variation of one-electron bandwidth ($W$). All the compounds exhibit the insulating ground state but undergo gradual insulatormetal ($I\ensuremath{-}M$) transitions at 500-700 K. Systematic variation of the $I\ensuremath{-}M$ transition temperatures (${T}_{\mathrm{IM}}$) as well as the thermal and optical charge gaps in the insulating phase have been observed with change of $R$ species (or equivalently $W$). Anomalously low ${T}_{\mathrm{IM}}$ as compared with the charge gap in each $R\mathrm{Co}{\mathrm{O}}_{3}$ suggests that the $I\ensuremath{-}M$ transition should be viewed as a thermally induced Mott transition.