Quantum critical point in the Sc-doped itinerant antiferromagnet TiAu

Abstract

We present an experimental realization of a quantum critical point in an itinerant antiferromagnet composed of nonmagnetic constituents, TiAu. By partially substituting Ti with Sc in ${\mathrm{Ti}}_{1\ensuremath{-}x}{\mathrm{Sc}}_{x}\mathrm{Au}$, a doping amount of ${x}_{c}=0.13\ifmmode\pm\else\textpm\fi{}0.01$ induces a quantum critical point with minimal disorder effects. The accompanying non-Fermi liquid behavior is observed in both the resistivity $\ensuremath{\rho}\ensuremath{\propto}T$ and specific heat ${C}_{p}/T\ensuremath{\propto}\ensuremath{-}\mathrm{ln}T$, characteristic of a two-dimensional antiferromagnet. The quantum critical point is accompanied by an enhancement of the spin fluctuations, as indicated by the diverging Sommerfeld coefficient $\ensuremath{\gamma}$ at $x={x}_{c}$.