Co-doped (BiSb)₂Te₃ thin films as next gen material for magnetoelectric transduction

Recent discoveries of magnetoelectric transduction effects in the antiferromagnetic insulator-heavy metal bilayer, MnF₂ - Pt, have demonstrated how spin excitations in MnF₂ can be detected electrically in a Pt overlayer through the inverse spin Hall effect. Pt is a commonly used metal for these devices due to its strong spin orbit coupling which enables spin Hall effects. Topological insulators have been demonstrated to generate spin currents significantly larger than in Pt due to the spin momentum locking effect in the surface states. Additionally, these surface states are truly 2D which causes all of the conduction to be at the MnF₂ interface. For these reasons, topological insulators could prove superior to Pt for generating magnetoelectric transduction effects. In this work, we present crystallographic, magnetic, and electronic characterizations of co-doped (BiSb)₂Te₃ films grown on MnF₂ thin films. From electronic transport measurements we demonstrate that the co-doped (BiSb)₂Te₃ films exhibit transport primarily through the 2D surface states. We also present evidence of magnetoelectric interactions due to the interface with MnF₂. Taken together these measurements demonstrate early work towards the realization of magnetoelectric transduction devices that utilize the unique properties of topological insulators