学术活动发布与订制系统

Here we show three experiments demonstrating the importance of interfacial electron-phonon coupling on the enhanced Tc of FeSe/STO. First, we observed replica bands in FeSe/STO (001) [4]. This indicates that there is strong electron-phonon coupling between monolayer FeSe and STO substrate, which may be pivotal for the Tc enhancement. Second, we observed polaron bands in STO (110) and monolayer FeSe/STO (110) [5]. This confirms the hypothesis of Zhou et al [6] that electron-phonon coupling is also essential in the FeSe/STO (110) system. Most conclusively, we grew highly strained 1ML FeSe on the rectangular (100) face of rutile TiO2, and observed the coexistence of replica bands and superconductivity with a Tc of 63 K [7]. From the similar Tc between this system and 1ML FeSe on STO, we conclude that strain and dielectric constant are likely unimportant to the enhanced Tc in these systems, and that interfacial coupling plays an essential role.

A systematic comparison of 1ML FeSe on TiO2 with other systems in the FeSe family can show that, while charge transfer alone can enhance Tc, it is only with the addition of interfacial electron-phonon coupling that Tc can be increased to the level seen in 1ML FeSe on STO.

Speaker:

Tao Jia, PhD student in Stanford University

Advisor: Professor Zhi-Xun Shen

Research interests: The MBE growth and ARPES/STM measurement of thin film of quantum materials, especially superconducting and topological heterostructures.

[1] Q. –Y. Wang et al., Chin. Phys. Lett. 29, 037402 (2012)

[2] F. –C. Hsu et al., PNAS 105, 14262 (2008)

[3] J. –F. Ge, et al., Nature Mater. 14, 285 (2014)

[4] J. J. Lee et al., Nature 515, 245 (2014)

[5] C. Zhang et al, arxiv preprint, 1608.01740 (2016)

[6] G. Zhou et al, Appl. Phys. Lett. 108, 202603 (2016)

[7] S. Rebec et al, arxiv preprint, 1606.09358 (2016)