Magnetic field frustration of the metal-insulator transition in V2O3

J. DEL VALLE; D. A. GILBERT; D. RAVELOSONA; J. TRASTOY; Y. KALCHEIM; J. A. BORCHERS; M. J. ROZENBERG; A. CAMJAYI; J.-P. CROCOMBETTE; J. E. VILLEGAS; I. K. SCHULLER

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2020 vol. 101 p. 245109 - 245109

1098-0121

Despite decades of efforts, the origin of metal-insulator transitions (MITs) in strongly correlated materials remains one of the main long-standing problems in condensed-matter physics. An archetypal example isV2O3, which undergoes simultaneous electronic, structural, and magnetic phase transitions. This remarkable feature highlights the many degrees of freedom at play in this material. In this work, acting solely on themagnetic degree of freedom, we reveal an anomalous feature in the electronic transport of V2O3: On cooling, the magnetoresistance changes from positive to negative values well above the MIT temperature, and shows divergent behavior at the transition. The effects are attributed to the magnetic field quenching antiferromagnetic fluctuations above the Néel temperature T_N, and preventing long-range antiferromagnetic ordering below T_N . In both cases, suppressing the antiferromagnetic ordering prevents the opening of the incipient electronic gap. Thisinterpretation is supported by Hubbard model calculations which fully reproduce the experimental behavior.Our study sheds light on this classic problem providing a clear and physical interpretation of the nature of the metal-insulator transition.