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arXiv · 2203.03901

Persistence of fermionic spin excitations through a genuine Mott transition in $\kappa$-type organics

Shusaku Imajo·Naoko Kato·Robert J. Marckwardt·Emre Yesil·Hiroki Akutsu·Yasuhiro Nakazawa
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Abstract

We investigate the continuous variation of electronic states from a Fermi liquid to a quantum spin liquid induced by chemical substitution in the organic dimer-Mott system of $\kappa$-[(BEDSe-TTF)$_x$(BEDT-TTF)$_{1-x}$]$_2$Cu[N(CN)$_2$]Br. Electrical transport measurements reveal that the mixing of BEDSe-TTF into the BEDT-TTF layers induces a quantum Mott transition around $x$=0.10. Although a charge gap disappears at this point, magnetic susceptibility and heat capacity measurements indicate that fermionic low-energy excitations remain in the insulating salts, suggesting that fermionic spin excitations persist. We propose that the transition can be classified into a genuine Mott transition.

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Shusaku Imajo, Naoko Kato, Robert J. Marckwardt, Emre Yesil, Hiroki Akutsu, Yasuhiro Nakazawa. 2022-03-08. Persistence of fermionic spin excitations through a genuine Mott transition in $\kappa$-type organics. https://doi.org/10.1103/physrevb.105.125130

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