Magnetic-field-induced insulator-metal transition in W-doped VO2 at 500 T
Magnetic-field-induced insulator-metal transition in W-doped VO2 at 500 T
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DOI：
10.1038/s41467-020-17416-w
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发表时间：
2020-07-17
影响因子：
16.6
通讯作者：
Muraoka, Yuji
中科院分区：
文献类型：
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作者：
Matsuda, Yasuhiro H.;Nakamura, Daisuke;Muraoka, Yuji
关联电子系统中的金属 - 绝缘体（MI）转变长期以来一直是材料科学中一个核心且有争议的问题。二氧化钒（VO₂）在340 K时呈现出一级金属 - 绝缘体转变。半个多世纪以来，对于这种金属 - 绝缘体转变背后更关键的驱动力是电子关联还是由于二聚化的V离子导致的结构不稳定性，一直存在争论。在此，我们表明500 T的超高磁场使掺钨（W）的VO₂的绝缘相变为金属相。V离子的d电子的自旋塞曼效应对绝缘相中的二聚体进行了解离，导致电子的离域。由于莫特 - 哈伯德能隙本质上不依赖于自旋自由度，结构不稳定性可能是金属 - 绝缘体转变背后更关键的驱动力。
Metal-insulator (MI) transitions in correlated electron systems have long been a central and controversial issue in material science. Vanadium dioxide (VO2) exhibits a first-order MI transition at 340 K. For more than half a century, it has been debated whether electron correlation or the structural instability due to dimerised V ions is the more essential driving force behind this MI transition. Here, we show that an ultrahigh magnetic field of 500 T renders the insulator phase of tungsten (W)-doped VO2 metallic. The spin Zeeman effect on the d electrons of the V ions dissociates the dimers in the insulating phase, resulting in the delocalisation of electrons. As the Mott-Hubbard gap essentially does not depend on the spin degree of freedom, the structural instability is likely to be the more essential driving force behind the MI transition.