Pseudogap and strong pairing induced by incipient and shallow bands in quasi-two-dimensional 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi mathvariant="normal">K</mml:mi><mml:msub><mml:mi>Ca</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Fe</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mi>As</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">F</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>

Hao, Jiahao; Hong, Wenshan; Zhou, Xianghui; Xiang, Ying; Dai, Y. M.; Yang, Huan; Li, Shiliang; Luo, Huiqian; Wen, Hao

doi:10.1103/physrevb.106.014523

Cited by 8 publications

(6 citation statements)

References 94 publications

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“…Consequently, the 12442 superconductor exhibits two different sites for As ions within the tetragonal unit cell, namely, As (1) and As(2), with a space group I4/mmm. [7,10] Upon cooling, KCa 2 Fe 4 As 4 F 2 exhibits superconductivity with a critical temperature (T c ) around 33 K. Notably, angle-resolved photoemission spectroscopy and specific heat experiments have revealed that this material possesses a complex electronic structure and multigap properties, [29,[32][33][34] consistent with the theoretical calculations. [35] However, the gap symmetry of KCa 2 Fe 4 As 4 F 2 remains a subject of controversy.…”

supporting

confidence: 67%

Coevolution of superconductivity and Hall coefficient with anisotropic lattice shrinkage in compressed KCa₂Fe₄As₄F₂

Han 韩,

Hong 洪,

Cai 蔡

et al. 2024

Chinese Phys. B

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It is well known that the stability of superconductivity in superconductors is widely recognized to be determined by various factors, including charge, spin, orbit, lattice, and other related degrees of freedom. Here, we report our findings on the pressure-induced coevolution of superconductivity and Hall coefficient in KCa2Fe4As4F2, an iron-based superconductor possessing a hybrid crystal structure combining KFe2As2 and CaFeAsF. Our investigation, involving high-pressure resistance, Hall effect and X-ray diffraction (XRD) measurements, allows us to observe the connection of the superconductivity and Hall coefficient with the anisotropic lattice shrinkage. We find that its ambient-pressure tetragonal (T) phase presents a collapse staring at around 18 GPa, where the sign of the Hall coefficient (R H ) changes from positive to negative. Upon further compression, both superconducting transition temperature (Tc) and R H exhibit a monotonous decrease. At around 41 GPa, the superconductivity is completely suppressed (T c =0), where the parameter a begins to decline again and the Hall coefficient remain nearly unchanged. Our experiment results clearly demonstrate that the pressure-induced anisotropic lattice collapse plays a curial role in tuning the interplay among multiple degrees of freedom in the superconducting system and, correspondingly, the stability of the superconductivity.

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supporting

confidence: 67%

Coevolution of superconductivity and Hall coefficient with anisotropic lattice shrinkage in compressed KCa₂Fe₄As₄F₂

Han 韩,

Hong 洪,

Cai 蔡

et al. 2024

Chinese Phys. B

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“…Furthermore, similar to cuprates, a relatively high anisotropy near , > 10, high Ginzburg number, 0.1 and small superfluid density are also observed in the 10-3-8 phase 26 – 28 . Such high anisotropy was also observed in another iron pnictide KCa Fe As F , which has a bilayer structure and a possible pseudogap behavior similar to BSCCO 29 – 31 . Moreover, interesting vortex dynamics behaviour has also been observed in a recent study on anisotropic KCa Fe As F compound 32 .…”

Section: Introductionsupporting

confidence: 59%

Order–disorder phase transition and elastic-to-plastic vortex creep crossover in a triclinic iron pnictide superconductor (Ca$$_{0.85}$$La$$_{0.15}$$)$$_{10}$$(Pt$$_3$$As$$_8$$)(Fe$$_2$$As$$_2$$)$$_5$$

Sundar,

Lopes,

Salem-Sugui

et al. 2023

Sci Rep

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Vortex matter in layered high-$$T_c$$ T c superconductors, including iron-pnictides, undergo several thermodynamic phase transitions due to the complex interplay of pinning energy, thermal energy and elastic energy. Moreover, the presence of anisotropy makes their vortex physics even more intriguing. Here, we report a detailed vortex dynamics study, using dc magnetization measurements, in a triclinic iron-pnictide superconductor (Ca$$_{0.85}$$ 0.85 La$$_{0.15}$$ 0.15 )$$_{10}$$ 10 (Pt$$_3$$ 3 As$$_8$$ 8 )(Fe$$_2$$ 2 As$$_2$$ 2 )$$_5$$ 5 , with a superconducting transition temperature, T$$_c$$ c $$\sim$$ ∼ 31 K. A second magnetization peak (SMP) feature is observed for magnetic field perpendicular (H$$\parallel$$ ‖ c) and parallel (H$$\parallel$$ ‖ ab) to the crystal plane. However, its fundamental origin is quite different in both directions. For H$$\parallel$$ ‖ c, the SMP can be well explained using an elastic-to-plastic vortex creep crossover, using collective creep theory. In addition, a possible rhombic-to-square vortex lattice phase transition is also observed for fields in between the onset-field and peak-field related to the SMP. On the other hand, for H$$\parallel$$ ‖ ab, a clear signature of an order-disorder vortex phase transition is observed in the isothermal M(H) measurements at T$$\ge$$ ≥ 6 K. The disordered phase exhibits the characteristics of entangled pinned vortex-liquid. We construct a comprehensive vortex phase diagram by displaying characteristic temperatures and magnetic fields for both crystal geometries in this unique superconducting compound. Our study sheds light on the intricate vortex dynamics and pinning in an iron-pnictide superconductor with triclinic symmetry.

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“…Figure 3(a) shows an example of the Drude fit for the data at 5 K. The fitting curve is composed of two Drude terms (referred to as Drude 1 and Drude 2) characterized by small and large scattering rates, respectively. Such a fitting method by multiple Drude terms has been widely used in iron-based superconductors [41][42][43] and the recently discovered kagome superconductors [44] due to the multiband response. The two-Drude fit indicates that MnBi 4 Te 7 has two types of charge carriers with very different scattering rates.…”

Section: Resultsmentioning

confidence: 99%

Optical study of magnetic topological insulator MnBi₄Te₇

Liao 廖,

Shen 沈,

Qiu 邱

et al. 2023

Chinese Phys. B

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We present an infrared spectroscopy study of the magnetic topological insulator MnBi$_4$Te$_7$ with antiferromagnetic (AFM) order below the Néel temperature $T_{\rm N}$ = 13 K. Our investigation reveals that the low-frequency optical conductivity consists of two Drude peaks, indicating a response of free carriers involving multiple bands. Interestingly, the narrow Drude peak grows strongly as the temperature deceases, while the broad Drude peak remains relatively unchanged. The onset of interband transitions starts around 2000 cm$^{-1}$, followed by two prominent absorption peaks around 10 000 cm$^{-1}$ and 20 000 cm$^{-1}$. Upon cooling, there is a notable transfer of spectral weight from the interband trasntions to the Drude response. Below $T_{\rm N}$, the AFM transition gives rise to small anomalies of the charge response due to a band reconstruction. These findings provide valuable insights into the interplay between magnetism and the electronic properties in MnBi$_4$Te$_7$.

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Pseudogap and strong pairing induced by incipient and shallow bands in quasi-two-dimensional KCa2Fe4As4F2

Cited by 8 publications

References 94 publications

Coevolution of superconductivity and Hall coefficient with anisotropic lattice shrinkage in compressed KCa₂Fe₄As₄F₂

Coevolution of superconductivity and Hall coefficient with anisotropic lattice shrinkage in compressed KCa₂Fe₄As₄F₂

Order–disorder phase transition and elastic-to-plastic vortex creep crossover in a triclinic iron pnictide superconductor (Ca$$_{0.85}$$La$$_{0.15}$$)$$_{10}$$(Pt$$_3$$As$$_8$$)(Fe$$_2$$As$$_2$$)$$_5$$

Optical study of magnetic topological insulator MnBi₄Te₇

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Pseudogap and strong pairing induced by incipient and shallow bands in quasi-two-dimensional KCa2Fe4As4F2

Cited by 8 publications

References 94 publications

Coevolution of superconductivity and Hall coefficient with anisotropic lattice shrinkage in compressed KCa2Fe4As4F2

Coevolution of superconductivity and Hall coefficient with anisotropic lattice shrinkage in compressed KCa2Fe4As4F2

Order–disorder phase transition and elastic-to-plastic vortex creep crossover in a triclinic iron pnictide superconductor (Ca$$_{0.85}$$La$$_{0.15}$$)$$_{10}$$(Pt$$_3$$As$$_8$$)(Fe$$_2$$As$$_2$$)$$_5$$

Optical study of magnetic topological insulator MnBi4Te7

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Product

Resources

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Coevolution of superconductivity and Hall coefficient with anisotropic lattice shrinkage in compressed KCa₂Fe₄As₄F₂

Coevolution of superconductivity and Hall coefficient with anisotropic lattice shrinkage in compressed KCa₂Fe₄As₄F₂

Optical study of magnetic topological insulator MnBi₄Te₇