Hybridization-driven orthorhombic lattice instability in URu2Si2


Hybridization-driven orthorhombic lattice instability in URu2Si2

Yanagisawa, T.; Mombetsu, S.; Hidaka, H.; Amitsuka, H.; Akatsu, M.; Yasin, S.; Zherlitsyn, S.; Wosnitza, J.; Huang, K.; Janoschek, M.; Maple, M. B.

We have measured the elastic constant (C 11-C 12)/2 in URu2Si2 by means of high-frequency ultrasonic measurements in pulsed magnetic fields H ║ [001] up to 61.8 T in a wide temperature range from 1.5 to 116 K. We found a reduction of (C 11-C 12)/2 that appears only in the temperature and magnetic field region in which URu2Si2 exhibits a heavy-electron state and hidden order. This change in (C 11-C 12)/2 appears to be a response of the 5f electrons to an orthorhombic and volume conservative strain field εxxyy with Γ3 symmetry. This lattice instability is likely related to a symmetry-breaking band instability that arises due to the hybridization of the localized f electrons with the conduction electrons and is probably linked to the hidden-order parameter of this compound.

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Publ.-Id: 19464