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Fermi Surface With Dirac Fermions In Cafeasf Determined Via Quantum Oscillation Measurements

Title: Fermi Surface With Dirac Fermions In Cafeasf Determined Via Quantum Oscillation Measurements.
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Name(s): Terashima, Taichi, author
Hirose, Hishiro T., author
Graf, David, author
Ma, Yonghui, author
Mu, Gang, author
Hu, Tao, author
Suzuki, Katsuhiro, author
Uji, Shinya, author
Ikeda, Hiroaki, author
Type of Resource: text
Genre: Journal Article
Text
Journal Article
Date Issued: 2018-02-01
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Despite the fact that 1111-type iron arsenides hold the record transition temperature of iron-based superconductors, their electronic structures have not been studied much because of the lack of high-quality single crystals. In this study, we comprehensively determine the Fermi surface in the antiferromagnetic state of CaFeAsF, a 1111 iron-arsenide parent compound, by performing quantum oscillation measurements and band-structure calculations. The determined Fermi surface consists of a symmetry-related pair of Dirac electron cylinders and a normal hole cylinder. From analyses of quantum-oscillation phases, we demonstrate that the electron cylinders carry a nontrivial Berry phase pi. The carrier density is of the order of 10(-3) per Fe. This unusual metallic state with the extremely small carrier density is a consequence of the previously discussed topological feature of the band structure which prevents the antiferromagnetic gap from being a full gap. We also report a nearly linear-in-B magnetoresistance and an anomalous resistivity increase above about 30 T for B parallel to c, the latter of which is likely related to the quantum limit of the electron orbit. Intriguingly, the electrical resistivity exhibits a nonmetallic temperature dependence in the paramagnetic tetragonal phase ( T > 118 K), which may suggest an incoherent state. Our study provides a detailed knowledge of the Fermi surface in the antiferromagnetic state of 1111 parent compounds and moreover opens up a new possibility to explore Dirac-fermion physics in those compounds.
Identifier: FSU_libsubv1_wos_000423991000001 (IID), 10.1103/PhysRevX.8.011014 (DOI)
Keywords: superconductivity, magnetoresistance, crystals, lifeas, Strongly Correlated Materials, Superconductivity, Topological Insulators
Publication Note: The publisher's version of record is available at https://doi.org/10.1103/PhysRevX.8.011014
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_libsubv1_wos_000423991000001
Owner Institution: FSU
Is Part Of: Physical Review X.
2160-3308
Issue: iss. 1, vol. 8

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Terashima, T., Hirose, H. T., Graf, D., Ma, Y., Mu, G., Hu, T., … Ikeda, H. (2018). Fermi Surface With Dirac Fermions In Cafeasf Determined Via Quantum Oscillation Measurements. Physical Review X. Retrieved from http://purl.flvc.org/fsu/fd/FSU_libsubv1_wos_000423991000001