论文标题
抗铁磁半导体CRPS4的偏振拉曼光谱和复杂的拉曼张量
Polarized Raman Spectra and Complex Raman Tensors of Antiferromagnetic Semiconductor CrPS4
论文作者
论文摘要
硫代磷酸铬（CRPS4）是C_2^3空间组的单斜晶体，是一种三元分层半导体，光带gap为1.4 eV，并且在36 K以下表现出抗铁磁性，尽管它在光电和磁性应用中的潜在潜力，但它的磁性应用并未进行过磁性验证。在这项工作中，我们使用了457、514和633 nm的三个不同的激发波长进行了散装CRPS4的偏光拉曼光谱。通过化学蒸气传输方法生长的高质量晶体被机械剥落或抛光，以暴露三个正交晶体学方面。通过平行和交叉构型获得偏振拉曼光谱，并通过将样品围绕与每个刻面的表面旋转。在布里渊区中心的33个拉曼活跃模式（16 a和17 b）中，在平行（交叉）配置中观察到的19（8）个峰被分配为A（b）模式。使用三个方面的角度依赖性拉曼光谱确定了7个主要A模式的复合价值拉曼张量。结果也可以用于确定CRPS4的晶体学取向。
Chromium thiophosphate (CrPS4), a monoclinic crystal of C_2^3 space group, is a ternary layered semiconductor with an optical bandgap of 1.4 eV and exhibits antiferromagnetism below 36 K. Despite its potential in optoelectronic and magnetic applications, the symmetry of its lattice vibrations has not been systematically studied. In this work, we performed a polarized Raman spectroscopy of bulk CrPS4 using three different excitation wavelengths of 457, 514, and 633 nm. High-quality crystals grown by the chemical vapor transport method were mechanically exfoliated or polished to expose three orthogonal crystallographic facets. Polarized Raman spectra were obtained in parallel and cross configurations by rotating samples about the surface normal to each of the facets. Among 33 Raman active modes (16 A and 17 B) at the Brillouin zone center, 19 (8) peaks observed in the parallel (cross) configuration were assigned as A (B) modes. Complex-valued Raman tensors were determined for 7 major A modes using the angle-dependent Raman spectra of the three facets. The results can also be used in determining the crystallographic orientations of CrPS4 unequivocally.
