RT Journal Article
SR Electronic
T1 Characteristic signatures of quantum criticality driven by geometrical frustration
JF Science Advances
JO Sci Adv
FD American Association for the Advancement of Science
SP e1500001
DO 10.1126/sciadv.1500001
VO 1
IS 3
A1 Tokiwa, Yoshifumi
A1 Stingl, Christian
A1 Kim, Moo-Sung
A1 Takabatake, Toshiro
A1 Gegenwart, Philipp
YR 2015
UL http://advances.sciencemag.org/content/1/3/e1500001.abstract
AB Geometrical frustration describes situations where interactions are incompatible with the lattice geometry and stabilizes exotic phases such as spin liquids. Whether geometrical frustration of magnetic interactions in metals can induce unconventional quantum critical points is an active area of research. We focus on the hexagonal heavy fermion metal CeRhSn, where the Kondo ions are located on distorted kagome planes stacked along the c axis. Low-temperature specific heat, thermal expansion, and magnetic Grüneisen parameter measurements prove a zero-field quantum critical point. The linear thermal expansion, which measures the initial uniaxial pressure derivative of the entropy, displays a striking anisotropy. Critical and noncritical behaviors along and perpendicular to the kagome planes, respectively, prove that quantum criticality is driven be geometrical frustration. We also discovered a spin flop–type metamagnetic crossover. This excludes an itinerant scenario and suggests that quantum criticality is related to local moments in a spin liquid–like state.