Erbium and thulium on MgO(100)/Ag(100) as candidates for single atom qubits

Abstract

Lanthanide atoms on surfaces are prospective platforms for realizing atomic-scale quantum logic units. Here, the authors combine scanning tunneling microscopy, x-ray magnetic circular dichroism, density functional theory, and atomic multiplet calculations to identify the quantum level structure of erbium and thulium atoms on MgO(100)/Ag(100), and to estimate their performance as spin qubits. Their analysis reveals that both atoms have a ground state that is suitable to perform efficient quantum coherent operations.