LaCu${}_{6-x}$Ag${}_x$: A promising host of an elastic quantum critical point

Abstract

Structural properties of LaCu${}_{6-x}$Ag${}_x$ have been investigated using neutron and x-ray diffraction, and resonant ultrasound spectroscopy (RUS) measurements. Diffraction measurements indicate a continuous structural transition from orthorhombic ($Pnma$) to monoclinic ($P{2}_1/c$) structure. RUS measurements show softening of natural frequencies at the structural transition, consistent with the elastic nature of the structural ground state. The structural transition temperatures in LaCu${}_{6-x}$Ag${}_x$ decrease with Ag composition until the monoclinic phase is completely suppressed at $x_c$ = 0.225. All of the evidence is consistent with the presence of an elastic quantum critical point in LaCu${}_{6-x}$Ag${}_x$.

5 pages, 3 figures, one table

References in corpus (6)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• "Deconfined" quantum critical points
• Quantum criticality
• Ambient Pressure Structural Quantum Critical Point in the Phase Diagram of (Ca${}_x$Sr${}_{1-x}$)${}_3$Rh${}_4$Sn${}_{13}$
• Large isotropic negative thermal expansion above a structural quantum phase transition
• Candidate Elastic Quantum Critical Point in LaCu${}_{6-x}$Au${}_x$