准二维FePS和MnPS反铁磁半导体的声子与热学性质
Phonon and Thermal Properties of Quasi-Two-Dimensional FePS and MnPS Antiferromagnetic Semiconductors.
作者信息
Kargar Fariborz, Coleman Ece A, Ghosh Subhajit, Lee Jonathan, Gomez Michael J, Liu Yuhang, Magana Andres Sanchez, Barani Zahra, Mohammadzadeh Amirmahdi, Debnath Bishwajit, Wilson Richard B, Lake Roger K, Balandin Alexander A
机构信息
Phonon Optimized Engineered Materials (POEM) Center, Department of Electrical and Computer Engineering , University of California , Riverside , California 92521 , United States.
Mechanical Engineering Department and Materials Science and Engineering Program , University of California , Riverside , California 92521 , United States.
出版信息
ACS Nano. 2020 Feb 25;14(2):2424-2435. doi: 10.1021/acsnano.9b09839. Epub 2020 Jan 28.
We report results of investigation of the phonon and thermal properties of the exfoliated films of layered single crystals of antiferromagnetic FePS and MnPS semiconductors. Raman spectroscopy was conducted using three different excitation lasers with wavelengths of 325 nm (UV), 488 nm (blue), and 633 nm (red). UV-Raman spectroscopy reveals spectral features which are not detectable visible Raman light scattering. The thermal conductivity of FePS and MnPS thin films was measured by two different techniques: the steady-state Raman optothermal and transient time-resolved magneto-optical Kerr effect. The Raman optothermal measurements provided the orientation-average thermal conductivity of FePS to be 1.35 ± 0.32 W m K at room temperature. The transient measurements revealed that the through-plane and in-plane thermal conductivity of FePS are 0.85 ± 0.15 and 2.7 ± 0.3 W m K, respectively. The films of MnPS have higher thermal conductivity of 1.1 ± 0.2 W m K through-plane and 6.3 ± 1.7 W m K in-plane. The data obtained by the two techniques are in agreement and reveal strong thermal anisotropy of the films and the dominance of phonon contribution to heat conduction. The obtained results are important for the interpretation of electric switching experiments with antiferromagnetic materials as well as for the proposed applications of the antiferromagnetic semiconductors in spintronic devices.
我们报告了对反铁磁FePS和MnPS半导体层状单晶剥离薄膜的声子和热学性质的研究结果。使用波长为325 nm（紫外）、488 nm（蓝光）和633 nm（红光）的三种不同激发激光进行拉曼光谱分析。紫外拉曼光谱揭示了在可见拉曼光散射中无法检测到的光谱特征。通过两种不同技术测量了FePS和MnPS薄膜的热导率：稳态拉曼光热法和瞬态时间分辨磁光克尔效应。拉曼光热测量结果表明，室温下FePS的取向平均热导率为1.35±0.32 W m⁻¹ K⁻¹。瞬态测量结果显示，FePS的面内热导率和平面内热导率分别为0.85±0.15和2.7±0.3 W m⁻¹ K⁻¹。MnPS薄膜的面内热导率较高，为1.1±0.2 W m⁻¹ K⁻¹，平面内热导率为6.3±1.7 W m⁻¹ K⁻¹。两种技术获得的数据一致，揭示了薄膜强烈的热各向异性以及声子对热传导的主导作用。所得结果对于解释反铁磁材料的电开关实验以及反铁磁半导体在自旋电子器件中的拟应用具有重要意义。
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