Zocco, Diego A.
Löhneysen, Hilbert v.
Eilers, Felix, Grube, Kai, Zocco, Diego A., et al.. "Strain-Driven Approach to Quantum Criticality in AFe2As2 with A=K, Rb, and Cs." Physical Review Letters, 116, no. 23 (2016) American Physical Society: 237003. http://dx.doi.org/10.1103/PhysRevLett.116.237003.
The iron-based superconductors AFe2As2 with A=K, Rb, Cs exhibit large Sommerfeld coefficients approaching those of heavy-fermion systems. We have investigated the magnetostriction and thermal expansion of this series to shed light on this unusual behavior. Quantum oscillations of the magnetostriction allow identifying the band-specific quasiparticle masses which by far exceed the band-structure derived masses. The divergence of the Grüneisen ratio derived from thermal expansion indicates that with increasing volume along the series a quantum critical point is approached. The critical fluctuations responsible for the enhancement of the quasiparticle masses appear to weaken the superconducting state.
American Physical Society
Strain-Driven Approach to Quantum Criticality in AFe2As2 with A=K, Rb, and Cs
Physical Review Letters