中国物理B ›› 2026, Vol. 35 ›› Issue (1): 17401-017401.doi: 10.1088/1674-1056/ae1df1

• • 上一篇    

Doping dependence of resistivity, upper critical field and its anisotropy in overdoped Ba1-xKxFe2As2 (x = 0.6-1) single crystals

Ke Shi(史可)1,2, Wenshan Hong(洪文山)3, Yang Li(李阳)3,4, Minjie Zhang(张敏杰)1,2, Yongqi Han(韩永琦)1,2, Yu Zhao(赵宇)1,2, Jiating Wu(吴嘉挺)1,5, Ze Wang(王泽)1, Langsheng Ling(凌浪生)1, Chuanying Xi(郗传英)1, Li Pi(皮雳)1, Huiqian Luo(罗会仟)3,†, and Zhaosheng Wang(王钊胜)1,‡   

  1. 1 Anhui Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, China;
    2 University of Science and Technology of China, Hefei 230026, China;
    3 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    4 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China;
    5 Electronic and Mechanical Engineering, Fujian Polytechnic Normal University, Fuzhou 350300, China
  • 收稿日期:2025-10-11 修回日期:2025-11-07 接受日期:2025-11-11 发布日期:2025-12-29
  • 通讯作者: Huiqian Luo, Zhaosheng Wang E-mail:hqluo@iphy.ac.cn;zswang@hmfl.ac.cn
  • 基金资助:
    This work was supported by the National Key Research and Development Program of China (Grant Nos. 2024YFA1611100, 2023YFA1406100, and 2018YFA0704201), the Systematic Fundamental Research Program Leveraging Major Scientific and Technological Infrastructure, Chinese Academy of Sciences (Grant No. JZHKYPT-2021–08), the National Natural Science Foundation of China (Grant Nos. 11704385, 11874359, and 12274444), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB25000000), and Steady High Magnetic Field Facility Instrument and Equipment Renovation.

Doping dependence of resistivity, upper critical field and its anisotropy in overdoped Ba1-xKxFe2As2 (x = 0.6-1) single crystals

Ke Shi(史可)1,2, Wenshan Hong(洪文山)3, Yang Li(李阳)3,4, Minjie Zhang(张敏杰)1,2, Yongqi Han(韩永琦)1,2, Yu Zhao(赵宇)1,2, Jiating Wu(吴嘉挺)1,5, Ze Wang(王泽)1, Langsheng Ling(凌浪生)1, Chuanying Xi(郗传英)1, Li Pi(皮雳)1, Huiqian Luo(罗会仟)3,†, and Zhaosheng Wang(王钊胜)1,‡   

  1. 1 Anhui Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, China;
    2 University of Science and Technology of China, Hefei 230026, China;
    3 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    4 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China;
    5 Electronic and Mechanical Engineering, Fujian Polytechnic Normal University, Fuzhou 350300, China
  • Received:2025-10-11 Revised:2025-11-07 Accepted:2025-11-11 Published:2025-12-29
  • Contact: Huiqian Luo, Zhaosheng Wang E-mail:hqluo@iphy.ac.cn;zswang@hmfl.ac.cn
  • Supported by:
    This work was supported by the National Key Research and Development Program of China (Grant Nos. 2024YFA1611100, 2023YFA1406100, and 2018YFA0704201), the Systematic Fundamental Research Program Leveraging Major Scientific and Technological Infrastructure, Chinese Academy of Sciences (Grant No. JZHKYPT-2021–08), the National Natural Science Foundation of China (Grant Nos. 11704385, 11874359, and 12274444), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB25000000), and Steady High Magnetic Field Facility Instrument and Equipment Renovation.

摘要: Temperature-dependent resistivity, upper critical field $H_{\rm c2}$ and its anisotropy in overdoped superconducting Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_2$ ($x=0.6$-1) single crystals have been measured in steady magnetic fields up to 44 T and low temperatures down to 0.4 K. Analysis using both the quadratic term and power-law fitting demonstrates that the in-plane resistivity $\rho_{ab}(T)$ progressively approaches the Fermi-liquid $T^2$ behavior with increasing K doping and reaches a saturation plateau at $x \approx 0.8$. The temperature dependence of both $H^{ab}_{\rm{c2}}$ and $H^{c}_{\rm{c2}}$ follows the Werthamer-Helfand-Hohenberg model, incorporating orbital and spin paramagnetic effects. For $x \leq 0.8$, the orbital effect dominates for $H \parallel ab$, while the Pauli paramagnetic effect prevails for $H\parallel c$. For $x > 0.8$, the Pauli paramagnetic effect becomes dominant in both crystallographic directions. The anisotropy of $H_{\rm{c2}}(0)$ exhibits a discontinuity in its dependence on K doping concentration with a significant enhancement at $x=0.8$ and a maximum at $x=0.9$. These experimental results indicate that the electron correlation effect is enhanced in the heavily overdoped Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_2$ system where the underlying symmetries are broken due to the Fermi surface reconstruction before $x=0.9$.

关键词: BaK122 single crystals, high magnetic fields, upper critical field Hc2, magnetoresistance

Abstract: Temperature-dependent resistivity, upper critical field $H_{\rm c2}$ and its anisotropy in overdoped superconducting Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_2$ ($x=0.6$-1) single crystals have been measured in steady magnetic fields up to 44 T and low temperatures down to 0.4 K. Analysis using both the quadratic term and power-law fitting demonstrates that the in-plane resistivity $\rho_{ab}(T)$ progressively approaches the Fermi-liquid $T^2$ behavior with increasing K doping and reaches a saturation plateau at $x \approx 0.8$. The temperature dependence of both $H^{ab}_{\rm{c2}}$ and $H^{c}_{\rm{c2}}$ follows the Werthamer-Helfand-Hohenberg model, incorporating orbital and spin paramagnetic effects. For $x \leq 0.8$, the orbital effect dominates for $H \parallel ab$, while the Pauli paramagnetic effect prevails for $H\parallel c$. For $x > 0.8$, the Pauli paramagnetic effect becomes dominant in both crystallographic directions. The anisotropy of $H_{\rm{c2}}(0)$ exhibits a discontinuity in its dependence on K doping concentration with a significant enhancement at $x=0.8$ and a maximum at $x=0.9$. These experimental results indicate that the electron correlation effect is enhanced in the heavily overdoped Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_2$ system where the underlying symmetries are broken due to the Fermi surface reconstruction before $x=0.9$.

Key words: BaK122 single crystals, high magnetic fields, upper critical field Hc2, magnetoresistance

中图分类号:  (Mixed states, critical fields, and surface sheaths)

  • 74.25.Op
74.25.F- (Transport properties) 74.70.Xa (Pnictides and chalcogenides) 74.25.Dw (Superconductivity phase diagrams)