PT - JOURNAL ARTICLE
AU - Tokiwa, Yoshifumi
AU - Stingl, Christian
AU - Kim, Moo-Sung
AU - Takabatake, Toshiro
AU - Gegenwart, Philipp
TI - Characteristic signatures of quantum criticality driven by geometrical frustration
AID - 10.1126/sciadv.1500001
DP - 2015 Apr 01
TA - Science Advances
PG - e1500001
VI - 1
IP - 3
4099 - http://advances.sciencemag.org/content/1/3/e1500001.short
4100 - http://advances.sciencemag.org/content/1/3/e1500001.full
SO - Sci Adv2015 Apr 01; 1
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.