Phys.org December 5, 2024
Although this high Tc is thought to be associated with electron–phonon coupling (EPC), the microscopic coupling mechanism and its role in the superconductivity remain elusive. An international team of researchers (USA – UC Irvine, Princeton University, China, Sweden) atomically resolved the phonons at the FeSe/STO interface and uncovered new optical phonon modes, coupling strongly with electrons, in the energy range of 75–99 meV. These modes were characterized by out-of-plane vibrations of oxygen atoms in the interfacial double-TiOx layer and the apical oxygens in STO. Their results demonstrated that the EPC strength and superconducting gap of 1 uc FeSe/STO were closely related to the interlayer spacing between FeSe and the TiOx terminated STO. According to the researchers their findings shed light on the microscopic origin of the interfacial EPC and provide insights into achieving large and consistent Tc enhancement in FeSe/STO and potentially other superconducting systems… read more. TECHNICAL ARTICLE
Interface structure and vibrational spectra of superconducting 1 uc FeSe/STO. Credit: Nature volume 635, pages 332–336, 30 October 2024