Electron-hole asymmetry in Co- and Mn-doped SrFe2As2

Authors :: Kim, J. S.
Khim, Seunghyun
Kim, H. J.
Eom, M. J.
Law, J.
Kremer, R. K.
Shim, Ji Hoon
Kim, Kee Hoon
Publication Year :: 2010
Publisher :: arXiv, 2010.
Abstract: Phase diagram of electron and hole-doped SrFe2As2 single crystals is investigated using Co and Mn substitution at the Fe-sites. We found that the spin-density-wave state is suppressed by both dopants, but the superconducting phase appears only for Co (electron)-doping, not for Mn (hole)-doping. Absence of the superconductivity by Mn-doping is in sharp contrast to the hole-doped system with K-substitution at the Sr sites. Distinct structural change, in particular the increase of the Fe-As distance by Mn-doping is important to have a magnetic and semiconducting ground state as confirmed by first principles calculations. The absence of electron-hole symmetry in the Fe-site-doped SrFe2As2 suggests that the occurrence of high-Tc superconductivity is sensitive to the structural modification rather than the charge doping.<br />Comment: 7 pages, 6 figures