Shadow Bands and Tunneling Magnetoresistance in Itinerant Electron Ferromagnets

TL;DR

This paper investigates how spectral weight transfer in itinerant electron ferromagnets affects tunneling magnetoresistance, revealing shadow-band phenomena that explain temperature-dependent behaviors in magnetic tunnel junctions.

Contribution

It introduces the concept of shadow bands in itinerant ferromagnets and links their properties to temperature-dependent tunneling magnetoresistance effects.

Findings

Shadow bands are formed at finite temperatures in itinerant ferromagnets.

Shadow-band peaks are located near opposite-spin quasiparticle energies.

The phenomenon explains temperature dependence in magnetic tunnel junctions.

Abstract

In itinerant electron ferromagnets spectral weight is transferred at finite temperatures from quasiparticle peaks located at majority and minority-spin band energies to shadow-band peaks. For a given Bloch wavevector and band index, the majority-spin shadow-band peak is located near the minority-spin quasiparticle energy and the minority-spin shadow-band peak is located near the majority-spin quasiparticle energy. This property can explain much of the temperature dependence seen in the magnetoresistance of magnetic tunnel junctions.