Charge-driven first-order magnetic transition in NiPS3

• Published in: Journal of physics. Condensed matter 2024-11, Vol.37 (5)
• Main Authors: Hwang, Junik, Park, Seonghoon, Hyun Kim, Beom, Kim, Junghyun, Park, Je-Geun, Baek, Seung-Ho
• Format: Article
• Language: English
• Subjects: first-order magnetic transition; magnetic van der Waals; nuclear magnetic resonance; Zhang-Rice exciton
• ISSN: 0953-8984; 1361-648X; 1361-648X
• DOI: 10.1088/1361-648X/ad8ea0

Cross-coupling among the fundamental degrees of freedom in solids has been a long-standing problem in condensed matter physics. Despite its progress using predominantly three-dimensional materials, how the same physics plays out for two-dimensional materials is unknown. Here, we show that using31P nuclear magnetic resonance (NMR), the van der Waals antiferromagnet NiPS3undergoes a first-order magnetic phase transition due to the strong charge-spin coupling in a honeycomb lattice. Our31P NMR spectrum near the Néel ordering temperatureTN=155 K exhibits the coexistence of paramagnetic and antiferromagnetic phases within a finite temperature range. Furthermore, we observed a discontinuity in the order parameter atTNand the complete absence of critical behavior of spin fluctuations aboveTN, decisively establishing the first-order nature of the magnetic transition. We propose that a charge stripe instability arising from a Zhang-Rice triplet ground state triggers the first-order magnetic transition.Cross-coupling among the fundamental degrees of freedom in solids has been a long-standing problem in condensed matter physics. Despite its progress using predominantly three-dimensional materials, how the same physics plays out for two-dimensional materials is unknown. Here, we show that using31P nuclear magnetic resonance (NMR), the van der Waals antiferromagnet NiPS3undergoes a first-order magnetic phase transition due to the strong charge-spin coupling in a honeycomb lattice. Our31P NMR spectrum near the Néel ordering temperatureTN=155 K exhibits the coexistence of paramagnetic and antiferromagnetic phases within a finite temperature range. Furthermore, we observed a discontinuity in the order parameter atTNand the complete absence of critical behavior of spin fluctuations aboveTN, decisively establishing the first-order nature of the magnetic transition. We propose that a charge stripe instability arising from a Zhang-Rice triplet ground state triggers the first-order magnetic transition.