Raman fingerprint of two terahertz spin wave branches in a two-dimensional honeycomb Ising ferromagnet

被引：119

作者：

Jin, Wencan ^{[1
]}

Kim, Hyun Ho ^{[2
,3
]}

Ye, Zhipeng ^{[4
]}

Li, Siwen ^{[1
]}

Rezaie, Pouyan ^{[4
]}

Diaz, Fabian ^{[4
]}

Siddiq, Saad ^{[4
]}

Wauer, Eric ^{[4
]}

Yang, Bowen ^{[2
,3
]}

Li, Chenghe ^{[5
,6
]}

Tian, Shangjie ^{[5
,6
]}

Sun, Kai ^{[1
]}

Lei, Hechang ^{[5
,6
]}

Tsen, Adam W. ^{[2
,3
]}

Zhao, Liuyan ^{[1
]}

He, Rui ^{[4
]}

机构：

[1] Univ Michigan, Dept Phys, 450 Church St, Ann Arbor, MI 48109 USA

[2] Univ Waterloo, Dept Chem, Inst Quantum Comp, 200 Univ Ave W, Waterloo, ON N2L 3G1, Canada

[3] Univ Waterloo, Dept Phys & Astron, 200 Univ Ave W, Waterloo, ON N2L 3G1, Canada

[4] Texas Tech Univ, Dept Elect & Comp Engn, 910 Boston Ave, Lubbock, TX 79409 USA

[5] Renmin Univ China, Dept Phys, Beijing 100872, Peoples R China

[6] Renmin Univ China, Beijing Key Lab Optoelect Funct Mat & Micronano D, Beijing 100872, Peoples R China

来源：

NATURE COMMUNICATIONS | 2018年 / 9卷

基金：

中国国家自然科学基金; 新加坡国家研究基金会; 加拿大自然科学与工程研究理事会; 美国国家科学基金会; 国家重点研发计划;

关键词：

SCATTERING; MAGNETISM; BEHAVIOR; CRYSTAL; LIGHT;

D O I：

10.1038/s41467-018-07547-6

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Two-dimensional (2D) magnetism has been long sought-after and only very recently realized in atomic crystals of magnetic van der Waals materials. So far, a comprehensive understanding of the magnetic excitations in such 2D magnets remains missing. Here we report polarized micro-Raman spectroscopy studies on a 2D honeycomb ferromagnet CrI3. We show the definitive evidence of two sets of zero-momentum spin waves at frequencies of 2.28 terahertz (THz) and 3.75 THz, respectively, that are three orders of magnitude higher than those of conventional ferromagnets. By tracking the thickness dependence of both spin waves, we reveal that both are surface spin waves with lifetimes an order of magnitude longer than their temporal periods. Our results of two branches of high-frequency, long-lived surface spin waves in 2D CrI3 demonstrate intriguing spin dynamics and intricate interplay with fluctuations in the 2D limit, thus opening up opportunities for ultrafast spintronics incorporating 2D magnets.

引用

页数：7

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