Field-induced staggered magnetic moment in the quasi-two-dimensional organic Mott insulator $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Cl

Abstract

We investigated the magnetism under a magnetic field in the quasi-two-dimensional organic Mott insulator $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Cl through magnetization and ${}^{13}$C-NMR measurements. We found that in the nominally paramagnetic phase (i.e., above Néel temperature) the field-induced local moments have a staggered component perpendicular to the applied field. As a result, the antiferromagnetic transition well defined at a zero field becomes crossover under a finite field. This unconventional behavior is qualitatively reproduced by the molecular-field calculation for Hamiltonian including the exchange, Dzyaloshinsky-Moriya (DM), and Zeeman interactions. This calculation also explains other unconventional magnetic features in $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Cl reported in the literature. The present results highlight the importance of the DM interaction in field-induced magnetism in a nominally paramagnetic phase, especially in low-dimensional spin systems.

11 pages, 12 figures, selected for Editors' Suggestions

References in corpus (5)

• Unconventional critical behaviour in a quasi-two-dimensional organic conductor
• Strong electronic correlations in superconducting organic charge transfer salts
• Amperean Pairing Instability in the U(1) Spin Liquid State with Fermi Surface and Application to $\kappa -(BEDT-TTF{)}_{2}C{u}_2(CN{)}_3$
• Emergence of inhomogeneous moments from spin liquid in the triangular-lattice Mott insulator $\kappa$-(ET)${}_2$Cu${}_2$(CN)${}_3$
• Gapless quantum spin liquid, stripe and antiferromagnetic phases in frustrated Hubbard models in two dimensions

Cited by in corpus (8)

• Anomalous Hall effect in $\kappa$-type organic antiferromagnets
• Importance of Spin-Orbit Coupling in Organic BEDT-TTF and BEDT-TSF Salts
• Electron spin dynamics of two-dimensional layered materials
• Charge disproportionation in the spin-liquid candidate $\kappa$-(ET)${}_2$Cu${}_2$(CN)${}_3$ at 6 K revealed by ${}^{63}$Cu NQR measurements
• Magneto-optical spectra of an organic antiferromagnet as a candidate for an altermagnet
• Anomalously field-susceptible spin soft-matter emerging in an electric-dipole liquid candidate
• Antiferromagnetic ordering of organic Mott insulator $\lambda$-(BEDSe-TTF)${}_2$GaCl${}_4$
• Persistence of fermionic spin excitations through a genuine Mott transition in $\kappa$-type organics