标题： 自旋液体和反铁磁序在Shastry-Sutherland晶格Yb$_{2}$Pt$_{2}$Pb中 显示英文标题

标题： Spin Liquids and Antiferromagnetic Order in the Shastry-Sutherland-Lattice Yb$_{2}$Pt$_{2}$Pb

摘要： 我们测量了金属\ypp 单晶的磁化率$\chi$和磁化强度 M，其中局域的 Yb 磁矩位于几何阻挫的 Shastry-Sutherland 晶格（SSL）上。 在这个准二维系统中发现了强磁阻挫，它从 Yb 双聚体的顺磁液态在 T$_{N}$=2.02 \emph{K}下反铁磁（AF）有序，单重态基态与三重态激发态之间存在能隙$\Delta$=4.6 \emph{K}。 磁场抑制 AF 有序，在 1.25 \emph{T}的量子临界点处消失。 自旋能隙$\Delta$在 1.5\emph{T}时仍然存在，表明在 T=0 时反铁磁性退化为二聚体三重态的液体。 在反铁磁态中观察到 M(B) 中的量子化台阶，这是 SSL 系统的特征。 我们的结果表明\ypp 是独特的，既作为一种接近反铁磁量子临界点的金属 SSL 系统，又作为一种几何阻挫起决定性作用的重费米子化合物。 显示英文摘要

摘要： We present measurements of the magnetic susceptibility $\chi$ and the magnetization M of single crystals of metallic \ypp, where localized Yb moments lie on the geometrically frustrated Shastry-Sutherland Lattice (SSL). Strong magnetic frustration is found in this quasi-two dimensional system, which orders antiferromagnetically (AF) at T$_{N}$=2.02 \emph{K} from a paramagnetic liquid of Yb-dimers, having a gap $\Delta$=4.6 \emph{K} between the singlet ground state and the triplet excited states. Magnetic fields suppress the AF order, which vanishes at a 1.25 \emph{T} quantum critical point. The spin gap $\Delta$ persists to 1.5 \emph{T}, indicating that the AF degenerates into a liquid of dimer triplets at T=0. Quantized steps are observed in M(B) within the AF state, a signature of SSL systems. Our results show that \ypp is unique, both as a metallic SSL system that is close to an AF quantum critical point, and as a heavy fermion compound where geometrical frustration plays a decisive role.