Direct observation of the energy gain underpinning ferromagnetic superexchange in the electronic structure of CrGeTe3

Journal article

We investigate the temperature-dependent electronic structure of the van der Waals ferromagnet, CrGeTe3. Using angle-resolved photoemission spectroscopy, we identify atomic- and orbital-specific band shifts upon cooling through 𝑇C. From these, together with x-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements, we identify the states created by a covalent bond between the Te 5⁢𝑝 and the Cr 𝑒𝑔 orbitals as the primary driver of the ferromagnetic ordering in this system, while it is the Cr 𝑡2⁢𝑔 states that carry the majority of the spin moment. The 𝑡2⁢𝑔 states furthermore exhibit a marked bandwidth increase and a remarkable lifetime enhancement upon entering the ordered phase, pointing to a delicate interplay between localized and itinerant states in this family of layered ferromagnets.

Authors: Watson, MD; Marković, I; Mazzola, F; Rajan, A; Morales, EA

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Physical Society
• Journal: Physical Review B
• Volume: 101
• Issue: 20
• Article number: 205125
• Publication date: 2020-05-18
• Acceptance date: 2020-04-16
• DOI: 10.1103/PhysRevB.101.205125
• EISSN: 2469-9969
• ISSN: 2469-9950
• Language: English
• Keywords: exchange interaction; magnetism; angle-resolved photoemission spectroscopy; Van der Waals systems; ferromagnets; x-ray magnetic circular dichroism