Pair density wave state in a monolayer high-Tc iron-based superconductor

Speaker

Prof. Jian Wang

Peking University                  

Time

4：00pm, August 30, 2023

Place

Material Science and Research Building B902

Dr. Jian Wang is a Boya Distinguished Professor of Physics at Peking University. He developed two laboratories at Peking University to perform ultralow temperature-high magnetic field transport measurements and low temperature scanning tunneling microscopy/spectroscopy-molecular beam epitaxy investigations. Dr. Jian Wang’s current research interests are quantum transport properties of low dimensional superconductors and topological materials. He has discovered a series of emergent quantum phase transitions and quantum states in both low dimensional superconductors and topological materials, including quantum Griffiths singularity, bosonic anomalous (quantum) metal state and topological zero energy bound states in two dimensional superconductors, as well as log-periodic quantum oscillations, high Chern number and high temperature Chern insulator states in topological materials. Dr. Jian Wang authored more than 120 papers in Science, Nature, Nature Physics, Nature Materials, Nature Nanotechnology, Science Advances, Nature Communications, PNAS, Physical Review X, Physical Review Letters, etc. He has given more than 100 invited talks and was awarded Sir Martin Wood China Prize in 2015, Changjiang Distinguished Professor of China's Ministry of Education in 2016, Outstanding Achievement Award for Research in Institutes of Higher Education of China (Young Scientists) in 2019, and the Achievement in Asia Award (Robert T. Poe Prize) in 2022. Homepage: https://faculty.pku.edu.cn/JianWangGroup

Abstract

The pair density wave (PDW) is an extraordinary superconducting state where Cooper pairs carry nonzero momentum. Theoretically, the PDW order is hypothesized to play a fundamental role in high-temperature (high-Tc) cuprate superconductors, wherein experimental evidence of the PDW state has been reported. However, the evidence of PDW order is scarce in iron-based high-Tc superconductors and low dimensional superconductors. Here, using scanning tunneling microscopy/spectroscopy, we report the discovery of the PDW state in monolayer iron-based high-Tc Fe(Te,Se) films grown on SrTiO₃(001) substrates [1]. The PDW state with a period of λ ~ 3.6a_Fe (a_Fe is the distance between neighboring Fe atoms) is observed at the domain walls by the spatial electronic modulations of the local density of states, superconducting coherence peak height and gap energy. Moreover, the π-phase shift boundaries of the PDW state are observed near the vortices of the induced secondary charge density wave state, further demonstrating that the PDW state at the domain wall is a primary state. The discovery of the primary PDW state in the monolayer Fe(Te,Se) film provides a low-dimensional platform to study the PDW state and its interplay with the topological electronic states and unconventional high-Tc superconductivity.

[1] Yanzhao Liu, Tianheng Wei, Guanyang He, Yi Zhang, Ziqiang Wang, and Jian Wang. Nature 618, 934-939 (2023).