Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in underdoped Bi2Sr2CaCu2O8+δ

Journal Article · Mon Sep 18 00:00:00 EDT 2023 · National Science Review

DOI:https://doi.org/10.1093/nsr/nwad249· OSTI ID:2333070

Wang, Shiyuan; Yu, Yijun; Hao, Jinxiang; Liang, Keyi; Xiang, Bingke; Zhu, Jinjiang; Lin, Yishi; Pan, Yinping; Gu, Genda; Watanabe, Kenji; Taniguchi, Takashi; Qi, Yang; Zhang, Yuanbo; Wang, Yihua

ABSTRACT

Superconducting phase transitions in two dimensions lie beyond the description of the Ginzburg-Landau symmetry-breaking paradigm for three-dimensional superconductors. They are Berezinskii-Kosterlitz-Thouless (BKT) transitions of paired-electron condensate driven by the unbinding of topological excitations, i.e. vortices. The recently discovered monolayers of layered high-transition-temperature ($${{{T}}}_{{\rm C}}$$) cuprate superconductor Bi2Sr2CaCu2O8+δ (Bi2212) meant that this 2D superconductor promised to be ideal for the study of unconventional superconductivity. But inhomogeneity posed challenges for distinguishing BKT physics from charge correlations in this material. Here, we utilize the phase sensitivity of scanning superconducting quantum interference device microscopy susceptometry to image the local magnetic response of underdoped Bi2212 from the monolayer to the bulk throughout its phase transition. The monolayer segregates into domains with independent phases at elevated temperatures below $${{{T}}}_{{\rm C}}$$. Within a single domain, we find that the susceptibility oscillates with flux between diamagnetism and paramagnetism in a Fraunhofer-like pattern up to $${{{T}}}_{{\rm C}}$$. The finite modulation period, as well as the broadening of the peaks when approaching $${{{T}}}_{{\rm C}}$$ from below, suggests well-defined vortices that are increasingly screened by the dissociation of vortex-antivortex plasma through a BKT transition. In the multilayers, the susceptibility oscillation differs in a small temperature regime below $${{{T}}}_{{\rm C}}$$, consistent with a dimensional crossover led by interlayer coupling. Serving as strong evidence for BKT transition in the bulk, we observe a sharp jump in phase stiffness and paramagnetism at small fields just below $${{{T}}}_{{\rm C}}$$. These results unify the superconducting phase transitions from the monolayer to the bulk underdoped Bi2212, and can be collectively referred to as the BKT transition with interlayer coupling.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: National Natural Science Foundation of China (NSFC); USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0012704
• OSTI ID: 2333070
• Alternate ID(s): OSTI ID: 2315622; OSTI ID: 2290421
• Report Number(s): BNL--225339-2024-JAAM; nwad249
• Journal Information: National Science Review, Journal Name: National Science Review Journal Issue: 5 Vol. 11; ISSN 2095-5138
• Publisher: Oxford University Press
• Country of Publication: China
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
Berezinskii-Kosterlitz-Thouless transition
cuprate superconductor
monolayer
paramagnetic Meissner effect
scanning SQUID