Measurement of coherent polarons in the strongly coupled antiferromagnetically ordered iron-chalcogenide Fe1.02Te using angle-resolved photoemission spectroscopy

• Published in: Physical review letters Vol. 110; no. 3; p. 037003
• Main Authors: Liu, Z K, He, R-H, Lu, D H, Yi, M, Chen, Y L, Hashimoto, M, Moore, R G, Mo, S-K, Nowadnick, E A, Hu, J, Liu, T J, Mao, Z Q, Devereaux, T P, Hussain, Z, Shen, Z-X
• Format: Journal Article
• Language: English
• Published: United States 18.01.2013
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.110.037003

The nature of metallicity and the level of electronic correlations in the antiferromagnetically ordered parent compounds are two important open issues for the iron-based superconductivity. We perform a temperature-dependent angle-resolved photoemission spectroscopy study of Fe(1.02)Te, the parent compound for iron chalcogenide superconductors. Deep in the antiferromagnetic state, the spectra exhibit a "peak-dip-hump" line shape associated with two clearly separate branches of dispersion, characteristics of polarons seen in manganites and lightly doped cuprates. As temperature increases towards the Néel temperature (T(N)), we observe a decreasing renormalization of the peak dispersion and a counterintuitive sharpening of the hump linewidth, suggestive of an intimate connection between the weakening electron-phonon (e-ph) coupling and antiferromagnetism. Our finding points to the highly correlated nature of the Fe(1.02)Te ground state featured by strong interactions among the charge, spin, and lattice and a good metallicity plausibly contributed by the coherent polaron motion.