Discovery of a bi-critical point between antiferromagnetic and superconducting phases in pressurized single crystal Ca0.73La0.27FeAs2

Abstract

One of the most strikingly universal features of the high temperature superconductors is that the superconducting phase emerges in the close proximity of the antiferromagnetic phase, and the interplay between these two phases poses a long standing challenge. It is commonly believed that,as the antiferromagnetic transition temperature is continuously suppressed to zero, there appears a quantum critical point, around which the existence of antiferromagnetic fluctuation is responsible for the development of the superconductivity. In contrast to this scenario, we report the discovery of a bi-critical point identified at 2.88 GPa and 26.02 K in the pressurized high quality single crystal Ca0.73La0.27FeAs2 by complementary in situ high pressure measurements. At the critical pressure, we find that the antiferromagnetism suddenly disappears and superconductivity simultaneously emerges at almost the same temperature, and that the external magnetic field suppresses the superconducting transition temperature but hardly affects the antiferromagnetic transition temperature.

arXiv comment15 pages and 4 figures

References in corpus (18)

• High-temperature superconductivity in iron-based materials
• A Common Thread: the pairing interaction for the unconventional superconductors
• The superconductivity at 18 K in LiFeAs system
• LiFeAs: An Intrinsic FeAs-based Superconductor with Tc = 18K
• Progress and perspectives on the electron-doped cuprates
• Quantum criticality
• Magnetism and its microscopic origin in iron-based high-temperature superconductors
• The electronic phase diagram of the LaO1-xFxFeAs superconductor
• The Challenge of Unconventional Superconductivity
• Superconductivity emerging from suppressed large magnetoresistant state in WTe2
• Reemerging superconductivity at 48 K across quantum criticality in iron chalcogenides
• SO(5) Theory of Antiferromagnetism and Superconductivity
• Superconductivity in Ca1-xLaxFeAs2: A Novel 112-Type Iron Pnictide with Arsenic Zigzag Bonds
• Discovery of New Layered Iron Arsenide Superconductor (Ca,Pr)FeAs2
• Presure-Induced Superconducting State of Antiferromagnetic CaFe${}_2$As${}_2$
• Doping-Enhanced Antiferromagnetism in Ca1-xLaxFeAs2
• Structural and magnetic phase transitions in Ca${}_{0.73}$La${}_{0.27}$FeAs${}_2$ with electron overdoped FeAs layers
• Instability of the O(5) multicritical behavior in the SO(5) theory of high-Tc superconductors