Electronic correlations in Rb-Fe-Se-S system
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TSURKAN, Vladimir, WIDMANN, S., GUNTHER, A., FILIPPOVA, Irina, KRAVTSOV, Victor, CROITORI, Dorina, KRUG VON NIDDA, Hans Albrecht, DEISENHOFER, Joachim, LOIDL, Alois. Electronic correlations in Rb-Fe-Se-S system. In: Materials Science and Condensed Matter Physics, Ed. 8-th Edition, 12-16 septembrie 2016, Chişinău. Chişinău: Institutul de Fizică Aplicată, 2016, Editia 8, p. 41. ISBN 978-9975-9787-1-2.
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Materials Science and Condensed Matter Physics
Editia 8, 2016
Conferința "International Conference on Materials Science and Condensed Matter Physics"
8-th Edition, Chişinău, Moldova, 12-16 septembrie 2016

Electronic correlations in Rb-Fe-Se-S system


Pag. 41-41

Tsurkan Vladimir12, Widmann S.2, Gunther A.2, Filippova Irina1, Kravtsov Victor1, Croitori Dorina1, Krug Von Nidda Hans Albrecht2, Deisenhofer Joachim2, Loidl Alois2
 
1 Institute of Applied Physics, Academy of Sciences of Moldova,
2 University of Augsburg
 
Disponibil în IBN: 18 iulie 2019


Rezumat

We report the growth and characterization of single crystals of Rb0.8Fe1.6Se2-xSx system with substitution of Se for S in the range 0 ≤ x ≤ 2. The single crystalline samples were grown by the Bridgman method. The composition of the samples was measured by the wave-length dispersive electron-probe microanalysis using Camebax SX50. The results of the structural study by the single crystal X-ray diffraction, Squid magnetometry (MPMS 5, Quantum Design), conductivity, and specific heat (PPMS, Quantum Design) are presented.     Anion substitution of Se for S in the K-Fe-Se system was shown to be an effective way to change the superconducting (SC) transition temperature [1]. Motivated by this unique possibility we looked for the structural and electronic correlations under varying substitution in Rb-Fe-Se-S system. The structural analysis revealed a decrease of both a and c lattice parameters with increasing substitution concentration x. A non-monotonic dependence of the occupation of the Fe positions vs. substitution was found with a minimum for the nearly fully occupied Fe1 sites and a maximum for the almost empty Fe2 sites at x =1.1 [2].   Fig. 1. Temperature dependence of the low field  susceptibility for samples with varying substitution Magnetic studies documented strong decrease of the SC transition temperature with the substitution (Fig. 1) with the disappearance of the superconductivity at x > 1.1. Similar to pure Rb0.8Fe1.6Se2, the SC Rb0.8Fe1.6Se2-xSx exhibit a strongly anisotropic antiferromagnetic (AFM) behavior below 400 K indicating the coexistence of superconductivity and static antiferromagnetic order. However, no macroscopic evidence for the SC stripes was found in the substituted samples. The specific heat of the SC samples exhibits aoticeable anomaly at the transition into the SC state suggesting bulk superconductivity. The resistivity studies found anon-monotonic temperature (T) dependence of the resistivity with a semiconducting behavior at high T, reaching a maximum at a sertain temperature and a metallic-like behavior at low T. The SC samples manifest a sharp drop in the resistivity correlating in T with the onset of the SC revealed by magnetization study. The evolution of the electronic correlations in Rb0.8Fe1.6Se2-xSx and the phase diagramm of the system is discussed within a scenario of the orbital-selective metalinsulator transition associated with quasiparticles with dxy orbital character which is based on the recent terahertz spectroscopy studies of these materials [3].