Li Ning, Zhang Chenhui, Liang Weizheng, Zhang Xixiang, Luo Sheng-Nian
School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, People's Republic of China.
Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
Nano Lett. 2022 May 25;22(10):3849-3855. doi: 10.1021/acs.nanolett.1c04064. Epub 2022 May 13.
Spin-phonon coupling is a fundamental interaction in ferromagnets/antiferromagnets and plays a key role in hot carrier decay. Normally, spin transfers its excess energy to a lattice via spin-phonon coupling in hot carrier decay in ferromagnets/antiferromagnets. However, the reverse energy transfer process (i.e., from lattice to spin) is feasible in principle but rarely reported. Here, we observe an abnormal hot carrier decay with a slow fall (80 ps) in Δ()/ time series in ferromagnet FeTaS, which is a result of the lattice of TaS vdW layer transfering its energy to spin via spin-phonon coupling. The Fe ions inserted between TaS vdW layers with very weak bonding with TaS vdW layer, are the origin of the ferromagnetism and give rise to its weak electron-spin and spin-phonon couplings which in turn lead to the observed abnormal hot carrier decay in the ferromagnetic phase FeTaS.
自旋-声子耦合是铁磁体/反铁磁体中的一种基本相互作用，在热载流子衰减中起关键作用。通常，在铁磁体/反铁磁体的热载流子衰减过程中，自旋通过自旋-声子耦合将其多余的能量转移给晶格。然而，反向能量转移过程（即从晶格到自旋）原则上是可行的，但很少有报道。在此，我们在铁磁体FeTaS的Δ()/时间序列中观察到一种异常的热载流子衰减，其下降缓慢（80皮秒），这是TaS范德华层的晶格通过自旋-声子耦合将其能量转移给自旋的结果。插入在TaS范德华层之间且与TaS范德华层结合非常弱的铁离子是铁磁性的起源，并导致其弱的电子自旋和自旋-声子耦合，进而导致在铁磁相FeTaS中观察到的异常热载流子衰减。
