Anion mixing effects on the electronic structure of a phosphorus-based Dirac nodal-line superconductor ZrP<sub>2-x</sub>Se<sub>x</sub>
ORAL
Abstract
Recently, a large family of superconductors emerged as mixed-anion layered phosphides, AP2-xXx (A = Zr, Hf; X = Se, S), which is based on nonsymmorphic phosphorus square-net lattice.
Here, we report our photoemission studies on the electronic structure of a typical phosphorus-based superconductor, ZrP2-xSex, with a critical temperature of Tc = 6.3 K. Core-level spectra reveal that the atomic charges of P are distinctly different between in-plane and mixed-anion sites. Valence-band spectra exhibit an upward energy shift of 0.49 eV in going from x = 0.85 to x = 0.55, indicating that replacing Se with P indeed serves as hole doping. Angle-resolved photoemission spectra unveil the presence of a diamond-shaped loop of Dirac nodal-line at 1.2 eV below Fermi level in direct analogy with a well-known Dirac nodal-line semimetal, ZrSiS, based on silicon square-net lattice. A simple model for the fundamental electronic structure of ZrP2-xSex is deduced from our experiments and calculations.
Our results indicate that the nonsymmorphic phosphorus square-net lattice provides a tunable platform for coexistence of the Dirac nodal line and the superconductivity.
Here, we report our photoemission studies on the electronic structure of a typical phosphorus-based superconductor, ZrP2-xSex, with a critical temperature of Tc = 6.3 K. Core-level spectra reveal that the atomic charges of P are distinctly different between in-plane and mixed-anion sites. Valence-band spectra exhibit an upward energy shift of 0.49 eV in going from x = 0.85 to x = 0.55, indicating that replacing Se with P indeed serves as hole doping. Angle-resolved photoemission spectra unveil the presence of a diamond-shaped loop of Dirac nodal-line at 1.2 eV below Fermi level in direct analogy with a well-known Dirac nodal-line semimetal, ZrSiS, based on silicon square-net lattice. A simple model for the fundamental electronic structure of ZrP2-xSex is deduced from our experiments and calculations.
Our results indicate that the nonsymmorphic phosphorus square-net lattice provides a tunable platform for coexistence of the Dirac nodal line and the superconductivity.
*This work was financially supported by JSPS KAKENHI (Grants Nos. 20K03842, 18H03683, 17H06138).The HAXPES experiments were performed at BL15XU of SPring-8 (Proposal Nos. 2015A4801, 2015B4800, 2016A4800, 2017B4801).The SX-ARPES experiments were performed at BL25SU of SPring-8 (Proposal Nos. 2021A1329, 2020A0803, 2019B1341).The VUV-ARPES experiments were performed at BL-1 of HiSOR (Proposal Nos. 21AG040, 21BG047)
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Publication: [1] A. Ino et al., Phys. Rev. B 105, 195111 (2022).
[2] S. Ishizaka et al., Phys. Rev. B 105, L121103 (2022).
Presenters
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Akihiro Ino
- Kurume Institute of Technology