Berlin 2012 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 17: Superconductivity: Fe-based Superconductors - 122 Part 2 & Theory
TT 17.4: Talk
Tuesday, March 27, 2012, 10:15–10:30, H 2053
In-plane anisotropy of electrical resistivity and thermoelectric power in underdoped EuFe2(As1−xPx)2 single crystals — •Shuai Jiang1,2, Hirale S. Jeevan1, Jannis Maiwald1, Martin Dressel2, and Philipp Gegenwart1 — 1I. Physikalisches Institut, Universität Göttingen, Germany — 21. Physikalisches Institut, Universität Stuttgart, Germany
We have studied the in-plane anisotropy of detwinned isovalent substituted EuFe2(As1−xPx)2 single crystals using a uniaxial pressure clamp. In the studied regime 0 < x ≤ 0.12 the structural and magnetic phase transitions are clearly separated. We reveal that the structural transition breaks the C4 rotational symmetry and induces nematic phase via the in-plane anisotropic measurements of resistivity and thermoelectric power. The observed anisotropy in both properties indicates the existence of nematic phase below the structural phase transition. A reconstruction of the Fermi surface below the magnetic transition is deduced by the thermopower anisotropy. Additionally, the resistivity anisotropy is larger than the orthorhombic distortion, indicating the difference of underlying electronic excitation near Fermi surface. The anisotropy below the Néel transition is caused by the intrinsic electronic structure, whereas the electronic nematicity plays an important role for the larger anisotropy above the Néel transition.