Orbital selective Mott phase and spin nematicity in Ni-substituted FeTe0.65Se0.35 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