2019/08/15 by Nina Andrejevic, Andrejevic, Nina, Fei Han +27
Materials Science · Physics and Astronomy · #Condensed matter physics #Coupling (piping) #FOS: Physical sciences #Heterojunction #Iron-based superconductors research #Magnetic and transport properties of perovskites and related materials #Materials science #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Optoelectronics #Phonon #Physics #Physics of Superconductivity and Magnetism #Raman spectroscopy #Spectroscopy #Superconductivity #cond-mat.mes-hall
paper · pdf · doi:10.48550/arxiv.1908.05648
16 pages, 4 main figures, 5 supplementary figures
arxiv created 2019/08/15 · openalex publication_date 2019/08/15 · arxiv updated 2019/08/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
The mechanism of enhanced superconductivity in the one unit-cell (1UC) FeSe film on a SrTiO3 (STO) substrate has stimulated significant research interest but remains elusive. Using low-temperature, voltage-gated Raman spectroscopy and low-temperature valence electron energy loss spectroscopy (VEELS), we characterize the phonon behavior and interfacial charge transfer in single- and few-layer FeSe films on STO. Raman measurements reveal ambipolar softening of the FeSe vibrational modes, mimicking that of the underlying STO substrate. We attribute this behavior to an interfacial coupling effect of STO on FeSe lattice dynamics. This interfacial coupling effect is further supported by local electron effective mass enhancement, which is determined from the red-shift in the FeSe VEELS spectrum near the FeSe/STO interface. Our work sheds light on the possible interfacial mechanisms contributing to the enhanced superconductivity across the FeSe/STO interface and further unveils the potential of low-temperature gated Raman spectroscopy and VEELS in clarifying a broad category of quantum materials.