Tai Trinh1,Rabindra Basnet2,Vignesh Chandrasekaran1,Xiangzhi Li1,Andrew Jones1,Jin Hu2,Han Htoon1
Los Alamos National Laboratory1,University of Arkansas, Fayetteville2
Tai Trinh1,Rabindra Basnet2,Vignesh Chandrasekaran1,Xiangzhi Li1,Andrew Jones1,Jin Hu2,Han Htoon1
Los Alamos National Laboratory1,University of Arkansas, Fayetteville2
A van der Waals correlated antiferromagnet, metal phosphorus trichalcogenides (MPX<sub>3</sub>, M = Mn, Fe, Ni; X = S, Se), have emerged as promising candidates for next-generation spintronics and quantum information technologies. Nickel phosphorus trisulfide (NiPS<sub>3</sub>) is a notable member of this family and has been extensively studied for its unique properties, including the emergence of an ultra-sharp photoluminescence (PL) peak at ~1.476 eV below the Néel temperature of 150 Kelvin. While the highly anisotropic, linearly polarized emission of this PL peak has been shown to be directly correlated to the long-range spin order of NiPS<sub>3</sub>, its ultra-narrow linewidth of a few hundred μeV has led to the speculation that it originates from a coherent many-body exciton state. Observations of multiple phonon-bound states and the formation of exciton-polaritons also create more excitement as they present new possibilities for the design and control of correlated electron systems.<br/> <br/>Aiming to understand how disturbances in the magnetic order of NiPS3 could influence the characteristics of this spin-correlated exciton emission, we conducted temperature-dependent polarization-resolved PL studies on alloyed Ni<sub>1-x</sub>Mn<sub>x</sub>PS<sub>3</sub> compounds, with Mn doping percentage x varying from 0 to 0.22. As the Mn content increases, we observe a reduction in the intensity of the ultra-sharp PL emissions, accompanied by a broadening of the PL linewidth from 0.57 meV (spectrometer resolution limit) to 4.2 meV. Notably, at x = 0.22, the previously sharp peak becomes negligible. Moreover, the degree of polarization also decreases as the Mn doping percentage increases. Temperature-dependent PL measurements reveal that the sharp emissions vanish at lower temperatures with higher Mn doping. These findings are consistent with prior studies of Ni<sub>1-x</sub>Mn<sub>x</sub>PS<sub>3</sub> alloy, revealing a highly sensitive dependence of the spin-flop transition on the inclusion of Mn impurities. We are currently conducting Magneto-PL and Raman spectroscopy experiments to gain further insights into this material system. Our studies clearly show that the spin-correlated exciton emission of NiPS<sub>3</sub> can serve as a sensitive sensor for the disturbance of the long-range spin order.