We have completely determined the Fermi surface in KFe2As2 via de Haas-van Alphen (dHvA) measurements. Fundamental frequencies ϵ, α, ζ, and β are observed in KFe2As2. The first one is attributed to a hole cylinder near the X point of the Brillouin zone, while the others to hole cylinders at the Γ point. We also observe magnetic breakdown frequencies between α and ζ and suggest a plausible explanation for them. The experimental frequencies show deviations from frequencies predicted by band structure calculations. Large effective masses up to 19 me for B∥c have been found, me being the free electron mass. The carrier number and Sommerfeld coefficient of the specific heat are estimated to be 1.01 -- 1.03 holes per formula unit and 82 -- 94 mJmol−1K−2, respectively, which are consistent with the chemical stoichiometry and a direct measure of 93 mJmol−1K−2 [H. Fukazawa \textit{et al}., J. Phys. Soc. Jpn. \textbf{80SA}, SA118 (2011)]. The Sommerfeld coefficient is about 9 times enhanced over a band value, suggesting the importance of low-energy spin and/or orbital fluctuations, and places KFe2As2 among strongly correlated metals. We have also performed dHvA measurements on Ba0.07K0.93Fe2As2 and have observed the α and β frequencies.
@article{arxiv.1304.6469,
title = {Fermi surface in KFe2As2 determined via de Haas-van Alphen oscillation measurements},
author = {Taichi Terashima and Nobuyuki Kurita and Motoi Kimata and Megumi Tomita and Satoshi Tsuchiya and Motoharu Imai and Akira Sato and Kunihiro Kihou and Chul-Ho Lee and Hijiri Kito and Hiroshi Eisaki and Akira Iyo and Taku Saito and Hideto Fukazawa and Yoh Kohori and Hisatomo Harima and Shinya Uji},
journal= {arXiv preprint arXiv:1304.6469},
year = {2013}
}