Thermodynamic evidence of fermionic behavior in the vicinity of one-ninth plateau in a kagome antiferromagnet

The spin-1/2 kagome Heisenberg antiferromagnets are believed to host exotic quantum entangled states. Recently, the report of 1/9 magnetization plateau and magnetic oscillations in a kagome antiferromagnet YCu\(_3\)(OH)\(_6\)Br\(_2\)[Br\(_x\)(OH)\(_{1-x}\)] (YCOB) have made this material a promising...

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Published inarXiv.org
Main Authors Zheng, Guoxin, Zhang, Dechen, Zhu, Yuan, Kuan-Wen, Chen, Chan, Aaron, Jenkins, Kaila, Kang, Byungmin, Zeng, Zhenyuan, Xu, Aini, Ratkovski, D, Blawat, Joanna, Bangura, Ali, Singleton, John, Lee, Patrick A, Li, Shiliang, Lu, Li
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 09.09.2024
Subjects
Antiferromagnetism
Density of states
Entangled states
Fermi surfaces
Heisenberg antiferromagnets
Magnetic fields
Specific heat
Spin liquid
Temperature dependence
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Summary:The spin-1/2 kagome Heisenberg antiferromagnets are believed to host exotic quantum entangled states. Recently, the report of 1/9 magnetization plateau and magnetic oscillations in a kagome antiferromagnet YCu\(_3\)(OH)\(_6\)Br\(_2\)[Br\(_x\)(OH)\(_{1-x}\)] (YCOB) have made this material a promising candidate for experimentally realizing quantum spin liquid states. Here we present measurements of the specific heat \(C_p\) in YCOB in high magnetic fields (up to 41.5 Tesla) down to 0.46 Kelvin, and the 1/9 plateau feature has been confirmed. Moreover, the temperature dependence of \(C_p/T\) in the vicinity of 1/9 plateau region can be fitted by a linear in \(T\) term which indicates the presence of a Dirac spectrum, together with a constant term, which indicates a finite density of states (DOS) contributed by other Fermi surfaces. Surprisingly the constant term is highly anisotropic in the direction of the magnetic field. Additionally, we observe a double-peak feature near \(30\)~T above the 1/9 plateau which is another hallmark of fermionic excitations in the specific heat.
ISSN:2331-8422