An Organic-Inorganic Hybrid Semiconducting Quantum Spin Liquid Candidate: (BEDT-TTF)3[Cu2(m-C2O4)3]·2CH3CH2OH

The organic-inorganic hybrid (BEDT-TTF)3[Cu2(m-C2O4)3]·2CH3CH2OH (I)was synthesized using the electrocrystallization method. It composes q21-phase organic donor layer and an inorganic antiferromagnetic honeycomb lattice with the Jahn-Teller distortion. The disordered solvent molecules CH3CH2OH are present within the cavities of the honeycomb lattice. The formal charge of donor molecules was assigned to +2/3 based on bond lengths in TTF core and corresponded to Raman spectra. Jahn-Teller effect on conductivity and magnetization is studied. It is a semiconductor with srt = 0.04 S/cm and Ea = 40 meV. No long-range ordering is observed above 2 K from zero-field cooling/field cooling magnetization and confirmed by specific heat measurement. The spin frustration with f > 10 from the antiferromagnetic copper-oxalate-framework was observed. It is a candidate for quantum spin liquid.