1. Probing electron quadrupling order through ultrasound
- Author
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Halcrow, Chris, Shipulin, Ilya, Caglieris, Federico, Li, Yongwei, Kihou, Kunihiro, Lee, Chul-Ho, Klauss, Hans-Henning, Zherlitsyn, Sergei, Grinenko, Vadim, and Babaev, Egor
- Subjects
Condensed Matter - Superconductivity ,Condensed Matter - Strongly Correlated Electrons ,Quantum Physics - Abstract
Recent experiments have pointed to the formation of a new state of matter, the electron quadrupling condensate in Ba$_{1-x}$K$_x$Fe$_2$As$_2$ . The state spontaneously breaks time-reversal symmetry and is sandwiched between two critical points, separating it from the superconducting and normal metal states. The adjacent two critical points make acoustic effects a promising tool to study such states because of their sensitivity to symmetry-breaking transitions. We report a theory of the acoustic effects of systems with an electron quadrupling phase and new ultrasound velocity measurements of Ba$_{1-x}$K$_x$Fe$_2$As$_2$ single crystals. The presented theory for the electron quadrupling state gives the same type of singularities that are observed in experiment., Comment: 11 pages, 6 figures
- Published
- 2024