Electric field gradient wave (EFGW) in iron-based superconductor Ba0.6K0.4Fe2As2 studied by Mossbauer spectroscopy

JOURNAL OF ALLOYS AND COMPOUNDS

卷:609

Article

Jasek, A. K.¹  Komedera, K.¹  Blachowski, A.¹  Ruebenbauer, K.¹  Bukowski, Z.²  Storey, J. G.^3,4  Karpinski, J.^5,6 

[1] Pedag Univ, Inst Phys, Mossbauer Spect Div, PL-30084 Krakow, Poland

[2] Polish Acad Sci, Inst Low Temp & Struct Res, PL-50422 Wroclaw, Poland

[3] Univ Cambridge, Cavendish Lab, Cambridge CB3 0HE, England

[4] Victoria Univ, Sch Chem & Phys Sci, Wellington, New Zealand

[5] ETH, Solid State Phys Lab, CH-8093 Zurich, Switzerland

[6] Ecole Polytech Fed Lausanne, Inst Condensed Matter Phys, CH-1015 Lausanne, Switzerland

关键词: Iron-based superconductors;    Mossbauer spectroscopy;    Strongly correlated electrons;   

DOI  :  10.1016/j.jallcom.2014.04.129

来源: Elsevier

【 摘 要 】

The optimally doped '122' iron-based superconductor Ba0.6K0.4Fe2As2 has been studied by Fe-57 Mossbauer spectroscopy versus temperature ranging from 4.2 K till 300 K with particular attention paid to the superconducting transition around 38 K. The spectra do not contain magnetic components and they exhibit quasi-continuous distribution of quadrupole split doublets. A distribution follows the electric field gradient (EFG) spatial modulation (wave) - EFGW. The EFGW is accompanied by some charge density wave (CDW) having about an order of magnitude lesser influence on the spectrum. The EFGW could be modeled as widely separated narrow sheets with the EFG increasing from small till maximum value almost linearly and subsequently dropping back to the original value in a similar fashion - across the sheet. One encounters very small and almost constant EFG between sheets. The EFGW shape and amplitude as well as the amplitude of CDW are strongly affected by a superconducting transition. All modulations are damped significantly at transition (38 K) and recover at a temperature being about 14 K lower. The maximum quadrupole splitting at 4.2 K amounts to about 2.1 mm/s, while the dispersion of CDW seen on the iron nuclei could be estimated far away from the superconducting gap opening and at low temperature as 0.5 el./a.u.(3). It drops to about 0.3 el./a.u.(3) just below transition to the superconducting state. (C) 2014 Elsevier B.V. All rights reserved.

【 授权许可】

Free