Bi2 Se3 thin films heteroepitaxially grown on +¦-RuCl3

Combining various two-dimensional materials into van der Waals (vdW) heterostructures has been shown to lead to emergent quantum systems. A heterostructure composed of a vdW topological insulator (TI) such as Bi2Se3 with a quantum spin liquid (QSL) such as +¦-RuCl3 is of great interest for the potential for the chiral Dirac electrons in the TI surface states to interact strongly with the fractionalized fermionic spin excitations in the QSL. We report the heteroepitaxial growth of Bi2Se3 thin films on +¦-RuCl3 as well as the characterization of their structural and electrical properties. Bi2Se3 thin films with an atomically smooth and uniform surface are grown by molecular beam epitaxy. The heterostructure exhibits a preferential epitaxial relationship corresponding to (5+ù5)-Bi2Se3/(23+ù23) R30-+¦-RuCl3 commensurate supercells with a periodicity of 1.2 nm. The formation of the superlattice despite a lattice mismatch as large as 60% is attributed to the vdW heteroepitaxy. Magnetotransport measurements as a function of temperature show Bi2Se3 films grown on +¦-RuCl3 are heavily n-doped, neGê+1014cm-2, with mobility ++ Gê+450cm2V-1s-1 at low temperatures.