# Magnon cotunneling through a quantum dot

## TL;DR

This paper investigates magnon cotunneling through a quantum dot strongly coupled to magnonic reservoirs, analyzing how magnetic fields and temperature differences influence magnon leakage currents, extending understanding beyond weak coupling regimes.

## Contribution

It introduces the concept of magnon cotunneling through a quantum dot with strong coupling, highlighting higher order processes and their dependence on magnetic and thermal conditions.

## Key findings

- Magnon cotunneling enables spin leakage currents in quantum dots.
- Magnetic field and temperature difference significantly affect magnon transport.
- Higher order processes are crucial in strongly coupled magnonic systems.

## Abstract

I consider a single-level quantum dot coupled to two reservoirs of spin waves (magnons). Such systems have been studied recently from the point of view of possible coupling between electronic and magnonic spin currents. However, usually weakly coupled systems were investigated. When coupling between the dot and reservoirs is not weak, then higher order processes play a role and have to be included. Here I consider cotunneling of magnons through a spin-occupied quantum dot, which can be understood as a magnon (spin) leakage current in analogy to leakage currents in charge-based electronics. Particular emphasis has been put on investigating the effect of magnetic field and temperature difference between the magnonic reservoirs.