Magnetic Frustration in the Shastry-Sutherland Kondo lattice and the Global Phase Diagram of Heavy Fermion Metals

Over the past decade there has been significant theoretical and experimental progress in our understanding of antiferromagnetic quantum critical heavy fermion metals [1]. Recent years have seen a surge of studies on heavy fermion compounds with local moments that reside on geometrically frustrated lattices, which may host entirely new types of quantum critical points [2]. With a particular emphasis on Yb$_{2}$Pt$_{2}$Pb [3] and related 221 systems [4,5], we consider the Shastry-Sutherland Kondo lattice [6]. We determine the zero temperature phase diagram as a function of magnetic frustration and Kondo coupling. We study the transition between the valence bond solid phase of the Shastry-Sutherland lattice and a heavy fermi liquid, and find a phase diagram remarkably similar to the theoretically proposed global phase diagram of heavy fermion metals. We discuss the implications of our results for other geometrically frustrated heavy fermion metals. \\[4pt] [1] Q. Si, J. H. Pixley, et al, J. Phys. Soc. Jpn. \textbf{83} 061005 (2014).\\[0pt] [2] Q. Si and F. Steglich, Science \textbf{329}, 1161 (2010).\\[0pt] [3] M. S. Kim and M. C. Aronson, Phys. Rev. Lett. \textbf{110}, 017201 (2013).\\[0pt] [4] J. G. Sereni et al, Phys. Rev. B81, 184429 (2010)\\[0pt] [5] T. Muramatsu et al, Phys. Rev. B83, 180404(R) (2011).\\[0pt] [6] J. H. Pixley, R. Yu and Q. Si, Phys. Rev. Lett. \textbf{113}, 176402 (2014).