Spontaneous Magnetic field and chiral superconductivity in BaPtAs<sub>1-x</sub>Sb<sub>x</sub> with honeycomb network
ORAL
Abstract
In recent years, a time-reversal symmetry-breaking superconducting (SC) state in which spontaneous magnetic field appears has attracted much attention. In materials with a so-called honeycomb network, the possibility of chiral d-wave superconductivity has been discussed [1]. Muon spin relaxation (μSR) is one of powerful tools for detecting spontaneous magnetic field.
In the layered pnictide BaPtAs1-xSbx with a honeycomb network, superconductivity appears over the entire range of x = 0 – 1.0 [2]. However, it has been unknown whether chiral d-wave superconductivity appears in this compound. Therefore, we performed μSR measurements on BaPtAs1-xSbx changing x widely [3].
It was found that the relaxation rate of muon spins increased below Tc = 1.7 K at x = 1.0, suggesting that spontaneous magnetic field is generated and time-reversal symmetry is broken. Moreover, the spontaneous magnetic field almost disappeared at x = 0.9, where a small amount of As was substituted for Sb, indicating that this superconductivity was weak to disorder. These suggest that the time-reversal symmetry-breaking SC state at x = 1.0 may have nodes on the SC gap. In the talk, I will compare these results with the band structure and Fermi surfaces obtained from the first-principles calculation and discuss the possibility of chiral d-wave superconductivity.
[1] P. K. Biswas et al. Phys. Rev. B 87, 180503(R) (2013).
[2] T. Ogawa et al., J. Phys. Soc. Jpn. 91, 123702 (2022).
[3] T. Adachi et al., submitted.
In the layered pnictide BaPtAs1-xSbx with a honeycomb network, superconductivity appears over the entire range of x = 0 – 1.0 [2]. However, it has been unknown whether chiral d-wave superconductivity appears in this compound. Therefore, we performed μSR measurements on BaPtAs1-xSbx changing x widely [3].
It was found that the relaxation rate of muon spins increased below Tc = 1.7 K at x = 1.0, suggesting that spontaneous magnetic field is generated and time-reversal symmetry is broken. Moreover, the spontaneous magnetic field almost disappeared at x = 0.9, where a small amount of As was substituted for Sb, indicating that this superconductivity was weak to disorder. These suggest that the time-reversal symmetry-breaking SC state at x = 1.0 may have nodes on the SC gap. In the talk, I will compare these results with the band structure and Fermi surfaces obtained from the first-principles calculation and discuss the possibility of chiral d-wave superconductivity.
[1] P. K. Biswas et al. Phys. Rev. B 87, 180503(R) (2013).
[2] T. Ogawa et al., J. Phys. Soc. Jpn. 91, 123702 (2022).
[3] T. Adachi et al., submitted.
*This work was partly supported by JSPS KAKENHI Grant Number JP19H05823, JP20K03826, JP22H01182 and by JST SPRING, Grant Number JPMJSP2152.
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Publication: "Spontaneous magnetic field and disorder effects in BaPtAs1−xSbx with honeycomb network", T. Adachi, T. Ogawa, Y. Komiyama, T. Sumura, Y. Saito-Tsuboi, T. Takeuchi, K. Mano, K. Manabe, K. Kawabata, T. Imazu, A. Koda, W. Higemoto, H. Okabe, J. G. Nakamura, T. U. Ito, R. Kadono, C. Baines, I. Watanabe, Y. Imai, J. Goryo, M. Nohara, and K. Kudo, submitted to Phys. Rev. B.
Presenters
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Tadashi Adachi
- Sophia University