Raman Spectroscopic Probe of the Magnetic Specific Heat in Quantum Magnets

Quasielastic Raman scattering arising from spin energy fluctuations is used to extract the magnetic specific heat. To test the applicability of a Raman scattering technique for probing magnetic specific heat, we choose three different classes of quantum magnets: (i) a quasi-1D s = 1/2 antiferromagnetic chain CuSe₂O₅, (ii) a 3D Kitaev honeycomb magnet γ-Li₂IrO₃, and (iii) a coupled-spin tetrahedral system Cu₂Te₂O₅Cl₂. Despite distinct dimensionality, spin topology, and spin-exchange type, the three materials show a pronounced quasielastic response commonly, enabling the determination of the magnetic contributions to the specific heat. Our work demonstrates that a Raman spectroscopic method is useful, complementing the conventional thermodynamic method, in deriving the magnetic specific heat in quantum magnets.