Manifestation of intra-atomic 5d6s-4f exchange coupling in photoexcited gadolinium. (17th November 2017)

• Record Type: Journal Article
• Authors: Zhang, G P; Jenkins, T; Bennett, M; Bai, Y H
• Is Part Of: Journal of physics. Volume 29:Number 49(2017)
• Publication Date: 2017-11-17
• Subjects: exchange coupling -- photoexcited -- femtomagnetism -- rare earth -- laser-induced -- ultrafast; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aa986c
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: Intra-atomic exchange couplings (IECs) between 5 d 6 s and 4 f electrons are ubiquitous in rare-earth metals and play a critical role in spin dynamics. However, detecting them in real time domain has been difficult. Here we show the direct evidence of IEC between 5 d 6 s and 4 f electrons in gadolinium. Upon femtosecond laser excitation, 5 d 6 s electrons are directly excited; their majority bands shift toward the Fermi level while their minority bands do the opposite. For the first time, our first-principles minority shift now agrees with the experiment quantitatively. Excited 5 d 6 s electrons lower the exchange potential barrier for 4 f electrons, so the 4 f states are also shifted in energy, a prediction that can be tested experimentally. Although a significant number of 5 d 6 s electrons, some several eV below the Fermi level, are excited out of the Fermi sea, there is no change in the 4 f states, a clear manifestation of intra-atomic exchange coupling.