Showing papers by "Anand Pal published in 2017"

Quantum spin fluctuations in the bulk insulating state of pure and Fe-doped SmB 6

Abstract: The intermediate-valence compound ${\mathrm{SmB}}_{6}$ is a well-known Kondo insulator, in which the hybridization of itinerant $5d$ electrons with localized $4f$ electrons leads to a transition from metallic to insulating behavior at low temperatures. Recent studies suggest that ${\mathrm{SmB}}_{6}$ is a topological insulator, with topological metallic surface states emerging from a fully insulating hybridized bulk band structure. Here, we locally probe the bulk magnetic properties of pure and $0.5%$ Fe-doped ${\mathrm{SmB}}_{6}$ by muon spin rotation/relaxation methods. Below 6 K, the Fe impurity induces simultaneous changes in the bulk local magnetism and the electrical conductivity. In the low-$T$ insulating bulk state we observe a temperature-independent dynamic relaxation rate indicative of low-lying magnetic excitations driven primarily by quantum fluctuations.