Revelation of the role of impurities and conduction electron density in the high resolution photoemission study of ferromagnetic hexaborides

Abstract

We investigate the temperature evolution of the electronic structure of ferromagnetic CaB${}_6$ using ultra-high resolution photoemission spectroscopy; electronic structure of paramagnetic LaB${}_6$ is used as a reference. High resolution spectra of CaB${}_6$ reveal finite density of states at the Fermi level, ${\epsilon }_F$ at all the temperatures and evidence of impurity induced localized features in the vicinity of ${\epsilon }_F$, which are absent in the spectra of LaB${}_6$. Analysis of the high resolution spectra suggests that disorder in B-sublattice inducing partial localization in the mobile electrons and low electron density at ${\epsilon }_F$ is important to achieve ferromagnetism in these systems.

arXiv comment4 figures

References in corpus (8)

• High-temperature ferromagnetism of $sp$ electrons in narrow impurity bands: Application to CaB${}_6$
• Excitonic ferromagnetism in the hexaborides
• CaB_6: a new semiconducting material for spin electronics
• Point defects, ferromagnetism and transport in calcium hexaboride
• Bulk Band Gaps in Divalent Hexaborides
• Origin of charge density wave formation in insulators from a high resolution photoemission study of BaIrO3
• Fermi Surface Measurements on the Low Carrier Density Ferromagnet Ca1-xLaxB6 and SrB6
• Electron-hole liquid in the hexaborides

Cited by in corpus (5)

• Role of vacancies and impurities in the ferromagnetism of semiconducting CaB6
• Effect of non-magnetic impurities on the magnetic states of anatase TiO${}_2$
• Magnetism and Antiferroelectricity in MgB${}_6$
• Aging of the surface of Bi(2)Se(3)
• Anomaly in the electronic structure of a BCS superconductor, ZrB(12)