Electronic scattering effects in europium-based iron pnictides

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• 作者：Sina Zapf^a ; ^{sina.zapf@pi1.physik.uni-stuttgart.de" class="auth_mail" title="E-mail the corresponding author} ; David Neubauer^a ; Kirk W. Post^b ; Alina Kadau^a ; Johannes Merz^a ; Conrad Clauss^a ; Anja Lö ; hle^a ; Hirale S. Jeevan^c ; ^d ; Philipp Gegenwart^c ; ^e ; Dimitri N. Basov^b ; Martin Dressel^a
• 关键词：Iron pnictides ; Electrodynamic properties ; Scattering ; Isovalent substitution ; Infrared ; Optical properties
• 刊名：Comptes Rendus Physique
• 出版年：2016
• 出版时间：January-February 2016
• 年：2016
• 卷：17
• 期：1-2
• 页码：188-196
• 全文大小：1276 K

文摘

In a comprehensive study, we investigate the electronic scattering effects in EuFe₂(As_1−xP_x)₂${\text{EuFe}}_2{({\text{As}}_{1-x}{\text{P}}_x)}_2$ by using Fourier-transform infrared spectroscopy. In spite of the fact that Eu²⁺${\text{Eu}}^{2+}$ local moments order at around T_Eu∼20 K$T_{\mathrm{Eu}}\sim 20\text{K}$, the overall optical response is strikingly similar to the one of the well-known Ba-122 pnictides. The main difference lies within the suppression of the lower spin-density-wave gap feature. By analyzing our spectra with a multi-component model, we find that the high-energy feature around 0.7 eV – often associated with Hund's rule coupling – is highly sensitive to the spin-density-wave ordering; this further confirms its direct relationship to the dynamics of itinerant carriers. The same model is also used to investigate the in-plane anisotropy of magnetically detwinned EuFe₂As₂${\text{EuFe}}_2{\text{As}}_2$ in the antiferromagnetically ordered state, yielding a higher Drude weight and lower scattering rate along the crystallographic a-axis. Finally, we analyze the development of the room-temperature spectra with isovalent phosphor substitution and highlight changes in the scattering rate of hole-like carriers induced by a Lifshitz transition.