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TT: Fachverband Tiefe Temperaturen

TT 93: Superconductivity – Poster II

TT 93.14: Poster

Thursday, March 12, 2026, 18:00–20:00, P4

nematic fluctuations and electronic correlations in heavily hole-doped Ba_1−xK_xFe₂As₂ probed by Elastoresistance — •Franz Eckelt¹, Xiaochen Hong^1,2, Steffen Sykora³, Vilmos Kocsis³, Vadim Grinenko⁴, Kunihiro Kihou⁵, Chul-Ho Lee⁵, Bernd Büchner³, and Christian Hess¹ — ¹University of Wuppertal, School of Mathematics and Natural Sciences, 42097 Wuppertal, Germany — ²Department of Applied Physics and Center of Quantum Materials and Devices, Chongqing University, 401331 Chongqing, China — ³Leibniz-Institute for Solid State and Materials Research, 01069 Dresden, Germany — ⁴Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 201210, China — ⁵National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan

We measure the elastoresistance of Ba_1−xK_xFe₂As₂ in the strongly hole-doped regime using longitudinal and transverse configurations. The subsequent symmetry decomposition of the elastoresistance reveals a crossover from dominant nematic fluctuations in the B_2g channel at low doping to a correlation-driven A_1g contribution that becomes visible for x > 0.7. Complementary multi-orbital model calculations reproduce this doping evolution and indicate that strengthened electronic correlations in the d_xy orbital govern the observed A_1g response in the heavily hole-doped regime.

Keywords: nematic fluctuations; Elastoresistance; Electronic correlations