AI 中文总结
研究二维三卤化铬及其三元合金，通过密度泛函理论研究其磁性相，发现纯化合物中不同磁性相带隙变化小，Cr原子磁矩递增，合金中FM态最低，带隙有弯曲，居里温度随成分变化，且合金形成在有限温度下热力学有利。
AI 中文摘要
二维磁性材料为探索低维自旋现象和下一代自旋电子器件提供了独特机会。三卤化铬CrX3（X = Cl、Br、I）是这类材料中的重要一族，合金化可为调整其电子、磁性、光学性质及热力学稳定性开辟途径。本文对CrX3化合物及其三元合金进行密度泛函理论研究。结果表明，纯化合物基态为铁磁（FM），反铁磁之字形（AFM-Z）和顺磁（PM）相能量相近。不同磁性相的带隙变化不超0.16 eV，Cr原子平均磁矩从Cl到Br再到I递增。合金中FM态仍是最低能量构型，但碘浓度较低的化合物与AFM-Z相的能量差减小。计算出的带隙沿连接CrCl3和CrI3的成分边缘有明显弯曲。居里温度随成分平滑变化，与磁交换参数的近似线性行为一致。基于计算出的混合焓和构型熵，近似吉布斯自由能表明合金形成在有限温度下在热力学上变得有利，这对克服这些化合物固有的实验不稳定性很重要。
英文摘要
Two-dimensional magnetic materials offer unique opportunities for exploring low-dimensional spin phenomena and next-generation spintronic devices. Chromium trihalides CrX3 (X = Cl, Br, I) belong to an important family of these materials, where alloying opens pathways for tailoring their electronic, magnetic, optical properties, and thermodynamic stability. In this work, we present a density functional theory study of CrX3 compounds and their ternary alloys. Our results show that for the pure compounds, the ground state is ferromagnetic (FM), with the antiferromagnetic-zigzag (AFM-Z) and paramagnetic (PM) phases being close in energy. For these pure systems, the band gap variation among different magnetic phases does not exceed 0.16 eV, and the average magnetic moments on Cr atoms increase from Cl to Br to I. For the alloys, the FM state remains the lowest-energy configuration, but the energy difference towards the AFM-Z phase decreases for compounds with lower iodine concentration. The calculated band gaps reveal a pronounced bowing along the compositional edge connecting CrCl3 and CrI3. The Curie temperatures show a smooth variation across compositions, consistent with the nearly linear behavior of the magnetic exchange parameters. Based on the calculated mixing enthalpy and configurational entropy, the approximate Gibbs free energy indicates that alloy formation becomes thermodynamically favorable at finite temperatures, which is important to overcome the intrinsic experimental instability of these compounds.
Comments29 pages, 9 figures, submitted to Physical Review Materials
