Electronic Structure of Pb Adsorbed Surfaces of Intrinsic Magnetic Topological Insulators

Abstract

Recently discovered intrinsic magnetic topological insulators (IMTIs) constitute a unique class of quantum materials that combine magnetism and nontrivial topology. One of the most promising applications of these materials is Majorana fermion creation; Majorana fermions are expected to arise when a superconductor is in contact with the surface of an IMTI. Here we study the adsorption of Pb ultrathin films on top of IMTIs of various stoichiometries. By means of XPS we figure out the formation of the Pb wetting layer coupled to the surface atoms for low coverages and overlayer growth on top upon further deposition. Investigation of the adsorbed surfaces by means of ARPES shows the Dirac cone survival, its shift in a binding energy, and the Pb electronic states appearance. The obtained results allow the Pb/IMTI interfaces to be constructed for the understanding of the proximity effect and provide an important step toward quantum device engineering based on IMTIs.

Fermiology of Chiral Cadmium Diarsenide CdAs2, a Candidate for Hosting Kramers–Weyl Fermions

“…Crystal symmetries play a pivotal role in determining the electronic properties of various quantum systems, and their study has garnered substantial interest for both fundamental research and technological applications. − Crystals exhibiting well-defined handedness, due to the breaking of inversion, mirror, or any other roto-inversion symmetries, are referred to as chiral crystals. − Even in their nonmagnetic state, these chiral crystals show universal topological electronic properties due to their spin–orbit coupling and crystalline chirality, resulting in the presence of Kramers–Weyl Fermions in their spectrum. , These Fermions are pinned to Kramers degenerate points, leading to the appearance of topological gaps, which are significantly larger than those observed in Weyl semimetals . Within such gaps, ubiquitous topological properties, such as quantized chiral charges, negative longitudinal magnetoresistance, and nontrivial Chern numbers can arise, opening up exciting avenues for engineering exotic transport phenomena and applications.…”

Physical Vapor Deposition Features of Ultrathin Nanocrystals of Bi2(TexSe1–x)3

“…For an effective realization of devices that exploit Dirac phenomena, the electron transport should be dominated by surface states as compared to the bulk. Ideally, the Fermi level should remain within the bulk gap between the valence and conduction bands. − The ability to fine-tune the Fermi level could result in significant progress in implementations of promising spin transport phenomena , in addition to gate-tunable − and Josephson transport devices. − However, the vast majority of compounds synthesized to date, such as Bi 2 Te 3 , and Bi 2 Se 3 , , have a trivial 3D band crossing the Fermi level and are rather thick crystals, both features leading to a detrimentally high bulk conductivity . The search for elaboration methods that address this issue is an important experimental challenge.…”