Thermal expansion and Grüneisen parameters of Ba(Fe(1-x)Co(x))2As2: a thermodynamic quest for quantum criticality.
Thermal expansion data are used to study the uniaxial pressure dependence of the electronic-magnetic entropy of Ba(Fe(1-x)Co(x))2As2. Uniaxial pressure is found to be proportional to doping and, thus, also an appropriate tuning parameter in this system. Many of the features predicted to occur for a pressure-tuned quantum critical system, in which superconductivity is an emergent phase hiding the critical point, are observed. The electronic-magnetic Grüneisen parameters associated with the spin-density wave and superconducting transitions further demonstrate an intimate connection between both ordering phenomena.
Institut für Festkörperphysik, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany. christoph.meingast@kit.edu
Christoph
C
Meingast
Frédéric
F
Hardy
Rolf
R
Heid
Peter
P
Adelmann
Anna
A
Böhmer
Philipp
P
Burger
Doris
D
Ernst
Rainer
R
Fromknecht
Peter
P
Schweiss
Thomas
T
Wolf