Abstract
Van der Waals magnets have been increasingly attracting huge interest in material science since several successful reports of monolayer magnetic systems were published in 2016. This new class of materials has been used to test some fundamental theorems of two-dimensional magnetism and novel applications [1, 2]. NiPS3 is a member of well-known antiferromagnets, TMPS3 with TM=Mn, Fe, Co, and Ni, which are good experimental demonstrations of Ising, XY, and Heisenberg models. NiPS3 is the first material produced on a monolayer and displays a clear sign of Mott physics, i.e., a strong spin-charge coupling [3, 4]. Another interest of NiPS3 is that it exhibits a striking magnetic exciton below TN=155 K, which is both coherent and strongly polarised. With many-body calculations, we could demonstrate that it arises from the quantum entangled states of the Zhang-Rice triplet/singlet states [5]. However, some questions remain about exciton, such as the doping effect [6]. I will discuss some reported works and the remaining issues in this talk.
References
[1] Je-Geun Park, J. Phys. Condens. Matter 28, 301001 (2016)
[2] Kenneth S. Burch, David Mandrus, and Je-Geun Park, Nature 563, 47 (2018)
[3] Cheng-Tai Kuo et al., Scientific Reports 6, 20904 (2016)
[4] So Yeun Kim et al., Phys. Rev. Lett. 120, 136402 (2018)
[5] Soonmin Kang et al., Nature 583, 785 (2020)
[6] Junghyun Kim et al., Nano Letters 23, 10189 (2023)
Please contact phweb@ust.hk should you have questions about the talk.
