Doping dependence of the Nernst effect in Eu(Fe1-xCox)(2)As-2: Departure from Dirac-fermion physics

作者：Matusiak Marcin^*; Bukowski Zbigniew; Karpinski Janusz

来源：Physical Review B, 2011, 83(22): 224505.

DOI：10.1103/PhysRevB.83.224505

We report a systematic study of the transport properties in the series of Eu(Fe1-xCox)(2)As(2)single crystals with x = 0, 0.15, 0.20, and 0.30. Spin-density-wave (SDW) order is observed in the undoped and the least doped samples with x = 0 and 0.15 at T-SDW = 191 and 131 K, respectively. For x = 0.15 and 0.20 Eu(Fe1-xCox)(2)As-2 becomes a superconductor with T-c(onset) = 20.5 and 8.5 K, respectively. We find properties of the SDW state in the parent EuFe2As2 compound well described by the Dirac-fermions model. On the other hand, the small cobalt doping significantly changes the transport coefficients below T-SDW in Eu(Fe0.85Co0.15)(2)As-2. Further increasing of x causes an evolution of the system toward a regular metallic state. The antiferromagnetic ordering of the Eu2+ ions at T-N approximate to 18 K has only minor influence on the measured quantities.

• 出版日期2011-6-21