Spin Andreev-like reflection in metal-Mott insulator heterostructures

TL;DR

This paper predicts and confirms a spin Andreev-like reflection in metal-Mott insulator heterostructures using tDMRG, extending the concept of Andreev reflection to magnetic systems and discussing potential experimental observations.

Contribution

It introduces the concept of spin Andreev reflection in heterostructures and demonstrates it numerically in 1D, suggesting its presence in higher dimensions and more general models.

Findings

Confirmation of spin Andreev reflection via tDMRG simulations

Proposal of an antiferromagnetic proximity effect

Discussion of experimental realization possibilities

Abstract

Using the time-dependent density-matrix renormalization group (tDMRG), we study the time evolution of electron wave packets in one-dimensional (1D) metal-superconductor heterostructures. The results show Andreev reflection at the interface, as expected. By combining these results with the well-known single-spin-species electron-hole transformation in the Hubbard model, we predict an analogous spin Andreev reflection in metal-Mott insulator heterostructures. This effect is numerically confirmed using 1D tDMRG, but it is expected to be present also in higher dimensions, as well as in more general Hamiltonians. We present an intuitive picture of the spin reflection, analogous to that of Andreev reflection at metal-superconductors interfaces. This allows us to discuss a novel antiferromagnetic proximity effect. Possible experimental realizations are discussed.