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arXiv · 2006.05221

Ferromagnetism out of charge fluctuation of strongly correlated electrons in $\kappa$-(BEDT-TTF)$_2$Hg(SCN)$_2$Br

Minoru Yamashita·Shiori Sugiura·Akira Ueda·Shun Dekura·Taichi Terashima·Shinya Uji·Yoshiya Sunairi·Hatsumi Mori·Elena I. Zhilyaeva·Svetlana A. Torunova·Rimma N. Lyubovskaya·Natalia Drichko·Chisa Hotta
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Abstract

We perform magnetic susceptibility and magnetic torque measurements on the organic $\kappa$-(BEDT-TTF)$_2$Hg(SCN)$_2$Br, which is recently suggested to host an exotic quantum dipole-liquid in its low-temperature insulating phase. Below the metal-insulator transition temperature, the magnetic susceptibility follows a Curie-Weiss law with a positive Curie-Weiss temperature, and a particular $M\propto \sqrt{H}$ curve is observed. The emergent ferromagnetically interacting spins amount to about 1/6 of the full spin moment of localized charges. Taking account of the possible inhomogeneous quasi-charge-order that forms a dipole-liquid, we construct a model of antiferromagnetically interacting spin chains in two adjacent charge-ordered domains, which are coupled via fluctuating charges on a Mott-dimer at the boundary. We find that the charge fluctuations can draw a weak ferromagnetic moment out of the spin singlet domains.

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Minoru Yamashita, Shiori Sugiura, Akira Ueda, Shun Dekura, Taichi Terashima, Shinya Uji, Yoshiya Sunairi, Hatsumi Mori, Elena I. Zhilyaeva, Svetlana A. Torunova, Rimma N. Lyubovskaya, Natalia Drichko, Chisa Hotta. 2020-06-09. Ferromagnetism out of charge fluctuation of strongly correlated electrons in $\kappa$-(BEDT-TTF)$_2$Hg(SCN)$_2$Br. https://doi.org/10.1038/s41535-021-00387-6

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