Open AccessAtomistic investigation of surface characteristics and electronic features at high-purity FeSi(110) presenting interfacial metallicity
Author(s) -
Biao Yang,
Martin Uphoff,
YiQi Zhang,
Joachim Reichert,
Ari P. Seitsonen,
Andreas Bauer,
C. Pfleiderer,
Johannes V. Barth
Publication year - 2021
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2021203118
Subject(s) - condensed matter physics , scanning tunneling microscope , silicide , materials science , fermi level , density functional theory , scanning tunneling spectroscopy , metallicity , band gap , electronic structure , surface states , semiconductor , density of states , surface (topology) , chemistry , physics , silicon , computational chemistry , electron , optoelectronics , astrophysics , stars , geometry , mathematics , quantum mechanics
Significance Iron silicide (FeSi) provides multiple fascinating features whereby intriguing functional properties bearing significant application prospects were recognized. FeSi is understood notably as a correlatedd -electron narrow-gap semiconductor and a putative Kondo insulator, hosting unconventional quasiparticles. Recently, metallic surface conduction channels were identified at cryogenic conditions and suggested to play a key role in the resistivity of high-quality single-crystalline specimens. Motivated by these findings, we prepared and closely examined a FeSi(110) surface with atomistically defined termination and topography. In the low-temperature regime, where surface metallicity emerges, the electronic band gap undergoes a subtle evolution. The pertaining key features, asymmetrization of the gap shape and formation of in-gap states, underscore the similarity of FeSi to unequivocal topological Kondo insulator materials.