2024/07/04 by Yuyan Han, Bing Yu, Han, Y. Y. +18
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Quantum many-body systems #Strongly Correlated Electrons (cond-mat.str-el) #Theoretical and Computational Physics #Topological and Geometric Data Analysis
paper · pdf · doi:10.48550/arxiv.2407.03581
openalex publication_date 2024/07/04 · openalex created_date 2024/07/09 · openalex updated_date 2026/07/28
Topologically nontrivial Haldane phase is theoretically proposed to be realized in the 1/3-magnetization (M) plateau of spin-1/2 trimer systems. However, the spin excitation gap, typical characteristic of Haldane phase, is not yet experimentally verified. Here, we report the nuclear magnetic resonance investigations into the low-energy spin dynamics in the S=1/2 spin-trimer antiferromagnetic chain compound Na2Cu3Ge4-xSixO12 (x=0, 0.1∼1.5). In the parent compound (x=0), the spin-lattice relaxation rate (1/T1) shows significantly different temperature dependence when the external magnetic field is increased above the critical field of μ0Hc = 29 T. The spin excitation gap is evidenced from the thermally activated behavior of 1/T1(T) in the 1/3-M plateau state. By substituting Ge4+ with Si4+, the critical field for the 1/3-M plateau significantly decreases, e.g. μ0Hc=17 T in x=1.0 samples, which results from the suppressed inter-trimer coupling J2. The gapped spin excitation is confirmed again above 17 T, whose size shows temperature-dependent behavior for μ0H≥25.72 T. These observations provide further insights into the Haldane physics.