Presentation Information
[PC1-01-INV]Bogoliubov quasiparticles and normal state gap in electron-doped cuprates
*Makoto Hashimoto Hashimoto1 (1. SLAC National Accelerator Lab (United States of America))
Keywords:
Cuprates,ARPES,Electron-doped cuprates,Superconducting gap,Pseudogap
The electron-doped cuprates are an important piece of the puzzle to understand high-transition-temperature cuprate superconductors. However, progress, particularly in advanced spectroscopy such as angle-resolved photoemission spectroscopy (ARPES), remains challenging due to the smaller temperature and energy scales as well as the sample surface quality [1]. In this talk, I will discuss the electronic structure of n-type cuprate Nd2-xCexCuO4, revealed by the much-improved ARPES experiments. Near the optimal doping, we directly observe the Bogoliubov quasiparticles. Within the antiferromagnetic pseudogap, we also observe gossamer states with distinct dispersion, from which coherence peaks of Bogoliubov quasiparticles emerge below the superconducting critical temperature, with the maximum superconducting gap an order of magnitude smaller than the pseudogap, establishing the distinct nature of these two gaps. We propose that orientation fluctuations in the antiferromagnetic order parameter are responsible for the gossamer states [2]. In the underdoped region, long-ranged antiferromagnetic order reconstructs the Fermi surface, resulting in a putative antiferromagnetic metal with small pockets. We observe an anomalous energy gap, an order of magnitude smaller than the antiferromagnetic gap, in a wide range of the underdoped regime and smoothly connecting to the superconducting gap at optimal doping (Fig. 1). After carefully considering all the known ordering tendencies in tandem with the phase diagram, we hypothesize that the normal state gap in the underdoped n-type cuprates originates from Cooper pairing. The high temperature scale of the normal state gap raises the prospect of engineering higher transition temperatures in the n-type cuprates comparable to that of the p-type cuprates [3].
1. J. A. Sobota, Y. He, Z.-X. Shen, Rev. Mod. Phys. 93, 025006 (2021).
2. K.-J. Xu et al., Nat Phys 19, 1834 (2023).
3. K.-J. Xu et al., Science 385, 796 (2024).
1. J. A. Sobota, Y. He, Z.-X. Shen, Rev. Mod. Phys. 93, 025006 (2021).
2. K.-J. Xu et al., Nat Phys 19, 1834 (2023).
3. K.-J. Xu et al., Science 385, 796 (2024).