Extended superconducting dome revealed by angle-resolved photoemission spectroscopy of electron-doped cuprates prepared by the protect annealing method

Ching Yih Lin ,K Koshiishi ,Yasuhiro Koike ,T Ohgi ,Masahiro Suzuki ,Hiroshi Kumigashira ,Koji Horiba ,Malik Anjelh Baqiya ,Takayuki Kawamata ,S Nakata ,Tadashi Adachi ,Kiyohisa Tanaka ,S Ideta ,K Hagiwara ,Kanta Ono ,Takuya Sumura ,Hidetaka Sato ,M Horio ,Goro Shibata ,A Fujimori

doi:10.1103/physrevresearch.3.013180

Abstract

The electron-doped cuprates are usually characterized by a more robust antiferromagnetic phase and a much narrower superconducting (SC) dome than those of the hole-doped counterparts. Recently, bulk single crystals of Pr1.3-xLa0.7CexCuO4-{\delta} (PLCCO) prepared by the protect annealing method have been studied extensively and revealed many intriguing properties that were different from those obtained from samples annealed by the conventional methods. Here, we report on a systematic angle-resolved photoemission spectroscopy study of PLCCO single crystals after protect annealing. The results indicate that the actual electron concentration (nFS ) estimated from the Fermi-surface area is significantly larger than the Ce concentration x and the new nFS-based SC dome of PLCCO is more extended towards the overdoped side than the x-based SC dome derived for samples prepared using the conventional annealing method.

Highlights

The discovery of the electron-doped cuprates guides a new way in unveiling the controversial physics of hightemperature superconductivity and motivates extensive experimental and theoretical studies for decades [1,2]
The results indicate that the actual electron concentration estimated from the Fermi-surface area is significantly larger than the Ce concentration x and the new nFS-based SC dome of PLCCO is more extended towards the overdoped side than the x-based SC dome derived for samples prepared using the conventional annealing method
The SC dome obtained in protect-annealed PLCCO is more extended on the overdoped side than that based on the conventional annealing method

Summary

INTRODUCTION

The discovery of the electron-doped cuprates guides a new way in unveiling the controversial physics of hightemperature superconductivity and motivates extensive experimental and theoretical studies for decades [1,2]. While AFM correlation still exists in the entire doping range, a new nFS-based phase diagram was proposed and shows a domelike SC region implying the possible absence of asymmetry between the phase diagrams of hole- and electron-doped cuprates. Comparing these two studies, one can see that, in the protect-annealed PLCCO [20,28,29], Tc is higher than that of the conventionally annealed samples [16], and no AFM pseudogap was found. The similarity between the new nFS-based SC dome and that of hole-doped LSCO has become clearer and provides a clue for understanding the symmetry/asymmetry of the cuprate phase diagram

EXPERIMENTAL CONDITIONS

RESULTS AND DISCUSSIONS

CONCLUSIONS