Glassy freezing of Ge-Ge dimerization in the kagome antiferromagnet FeGe

Kagome metals have recently garnered a great deal of attention owing to their highlyunconventional properties, leading to the emergence of intriguing quantum phases [1]. Forexample, the kagome materials AV
3
Sb
5
(A = K, Rb, Cs) [2] exhibit an interplay betweenunconventional superconductivity and charge-density-waves (CDW). Recently a CDW wasdiscovered in the antiferromagnetically ordered kagome metal FeGe [3-5]. Here, weinvestigate in detail the CDW in FeGe for various annealing temperatures using the high-resolution dilatometry. In addition to the CDW, a pronounced glassy transition is observedat lower temperatures, presumably due to the freezing of incomplete Ge-Ge dimerization.Complementary calorimetry and magnetization measurements will also be presented.
[1] T. Neupertet,et al. Nat. Phys. 18, 137–143 (2022)
[2] F. Mehdi, et al. Phys. Rev. Lett. 132, 186001 (2024)
[3] X. Tenget et al. . Nature 609, 490–495 (2022)
[4] Jia-Xin Yin, et al. Phys. Rev. Lett. 129, 166401 (2022)
[5] C. Setty, et al. arXiv:2203.01930