Orbital selective Mott phase and spin nematicity in Ni-substituted FeTe<sub>0.65</sub>Se<sub>0.35 </sub>single crystals
ORAL
Abstract
The normal state in iron chalcogenides is metallic but highly unusual, with orbital and spin degrees of freedom partially itinerant or localized depending on temperature, a consequence of multi-orbital character and Hund's interaction. The unusual phenomena include, between others, the orbital-selective Mott phase (OSMP), documented by angular resolved photoemission (ARPES) [1], and C4 symmetry breaking of in-plane angular magnetoresistance (AMR) [2].
We study these phenomena using magnetization and magnetotransport measurements (resistivity, Hall effect, AMR) in Fe1-yNiyTe0.65Se0.35 single crystals (0xy orbital. We show that electron-dominated transport, observed at low T at large y, is replaced by hole-dominated transport at T > 180 K, suggesting direct link with the appearance of the dz2 hole pockets at X points of the Brillouin zone in the OSMP phase, as recently reported [1]. The AMR shows the C4 rotational symmetry of in-plane magnetocrystalline anisotropy at small y, replaced by C2 symmetry at intermediate y, indicating development of spin nematicity induced by Ni doping, likely contributing to the suppression of superconductivity.
[1] J. Huang, et al., Commun. Phys. 5, 29 (2022).
We study these phenomena using magnetization and magnetotransport measurements (resistivity, Hall effect, AMR) in Fe1-yNiyTe0.65Se0.35 single crystals (0xy orbital. We show that electron-dominated transport, observed at low T at large y, is replaced by hole-dominated transport at T > 180 K, suggesting direct link with the appearance of the dz2 hole pockets at X points of the Brillouin zone in the OSMP phase, as recently reported [1]. The AMR shows the C4 rotational symmetry of in-plane magnetocrystalline anisotropy at small y, replaced by C2 symmetry at intermediate y, indicating development of spin nematicity induced by Ni doping, likely contributing to the suppression of superconductivity.
[1] J. Huang, et al., Commun. Phys. 5, 29 (2022).
[2] S. Liu, et al., Chin. Phys. Lett. 38, 087401 (2021).
[3] M. Rosmus et al., Supercond. Sci. Technol. 32, 105009 (2019).
*The work has been supported by Polish NSC Grant No. 2014/15/B/ST3/03889. The research was partially performed in the laboratory co-financed by the ERDFProject NanoFunPOIG.02.02.00-00-025/09.
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Publication: Marta Z. Cieplak, I. Zajcewa, A. Lynnyk, K. M. Kosyl, and D. J. Gawryluk, Disorder and nematicity in Ni-substituted FeTe0.65Se0.35 single crystals, preprint.
Presenters
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Marta Z Cieplak
- Institute of Physics, Polish Academy of Sciences