Emergent Rashba spin-orbit coupling in bulk gold with buried network of nanoscale interfaces

The Rashba effect, which plays a crucial role in fundamental materials physics and potential spintronics applications, has been engineered in diverse systems, including semiconductor quantum wells, oxide heterostructures, metallic surfaces, topological insulators, ferroelectrics, etc. However, generating it in systems that preserve bulk inversion symmetry (BIS), for example, in bulk metals, has not been possible so far. We demonstrate a unique strategy to introduce and tune Rashba spin-orbit interaction (SOI) to unprecedented magnitudes in inversion-symmetric solids, by incorporating ultra-small silver nanoparticles in bulk gold. The near-identical lattice constants of Ag and Au allowed dense packing of the Ag/Au hetero-interfaces without compromising the global BIS. By varying the density of embedded nanoparticles, we generate Rashba SOI in a bulk metal with coupling strength ∼15 meV∙Å, higher than any known system preserving BIS globally and up to ∼20 times increase in the spin-orbit ..., , , Files are stored in folders - each with a corresponding README.md. Fig1d: In the file of Fig.1d, we have filling fraction(F) on the X-axis and Y-axis shows residual resistivity, 𝜌0 (defined as the resistivity, 𝜌, at the base temperature 𝑇 ∼ 6 K). Fig1e: The files of Fig.1e show T-dependence of resistivity, 𝜌, for films with varying filling fraction, F. In the X-axis, we have temperatures(*T*), and the Y-axis shows resistivity, 𝜌. Fig2a: The files of Fig.2a show the Magnetoresistance (MR), represented by the relative change in resistivity ((𝜌(𝐵) − 𝜌(0))/𝜌 = Δ𝜌/𝜌) with magnetic field (𝐵), in a perpendicular magnetic field is measured for a film with Ag/Au interface density, 𝐹 = 0.09, at the various temperatures indicated. In the X-axis, we have magnetic field(B) and Y-axis shows magnetoresistance,((𝜌(𝐵) − 𝜌(0))/𝜌 = Δ𝜌/𝜌). Fig. 2 b: The files of folder Fig.2b show the Magnetoresistance(MR) at 𝑇 ∼ 1 K for different films with values of 𝐹 varying from 0 to 0.5. In the X-axis, we have th...