ScholarWorks@성균관대학교

초록

Quantum magnets offer a unique platform for exploring exotic quantum phases and quantum phase transitions through external magnetic fields. A prominent example is the field-induced Bose-Einstein condensation (BEC) of magnons near the saturation field. While this behavior has been observed in low-spin systems, its realization in high-spin, quasi-two-dimensional magnets-where multiple on-site excitations are possible-remains exceptionally rare. Here, we report thermodynamic and density functional theory results on single crystals of the honeycomb-lattice antiferromagnet K4MnMo4O15 with S = 52. The system undergoes a field-induced transition to a fully polarized state at the critical field mu 0Hs = 6.4 T. Our results reveal possible thermodynamic signatures of magnon BEC, TN similar to (Hs-H)2/d (d = 3), expanding the purview of BEC-driven quantum criticality to a high-spin, quasi-two-dimensional antiferromagnets with negligibly small anisotropy.

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