Magnetic-field-induced insulator-metal transition in W-doped VO2 at 500 T

• Published in: arXiv.org
• Main Authors: Matsuda, Yasuhiro H, Nakamura, Daisuke, Ikeda, Akihiko, Takeyama, Shojiro, Muraoka, Yuji, Suga, Yuki
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 23.01.2020
• Subjects: Dimers; Electron spin; Electrons; Insulators; Physics - Strongly Correlated Electrons; Structural stability; Tungsten; Vanadium dioxide; Vanadium oxides; Zeeman effect
• DOI: 10.48550/arxiv.2001.08580

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 electronic 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. Because 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.