Theory of asymmetric and negative differential magnon tunneling under temperature bias: Towards a spin Seebeck diode and transistor

TL;DR

This paper investigates how temperature-dependent magnon interactions cause asymmetric and negative differential spin Seebeck effects in magnon tunneling, enabling the design of spin diodes and transistors for magnonic applications.

Contribution

It reveals the role of many-body magnon interactions in generating rectification and negative differential effects, advancing the understanding of spin caloritronics devices.

Findings

Reversal of temperature bias leads to asymmetric spin currents.

Increasing temperature bias can decrease magnonic spin current.

Temperature-dependent density of states is key for rectification.

Abstract

We study the nonequilibrium transport for the asymmetric and negative differential magnon tunneling driven by temperature bias. We demonstrate that the many-body magnon interaction that makes the magnonic spectrum temperature-dependent is the crucial factor for the emergence of rectification and negative differential spin Seebeck effects in magnon tunneling junctions. When magnonic junctions have temperature-dependent density of states, reversing the temperature bias is able to give asymmetric spin currents and increasing temperature bias could give an anomalously decreasing magnonic spin current. We show that these properties are relevant for building spin Seebeck diodes and transistors, which could play important roles in controlling information and energy in magnonics and spin caloritronics.