arXiv subjects

L. T. Baczewski

Publications and source records attributed to L. T. Baczewski.

4 recordsLinked to original sources

arXiv2026

The geometry of the CISS effect

Using scanning tunneling microscopy, and a careful selection of chiral molecules and anchoring groups, we systematically carried out a series of magnetoresistance experiments. We observed a reversal of the signal upon changing the magnetization direction, the molecular chirality, and the molecular orientation. The orientation of the molecules and the magnetization of the substrate are vectors, and by associating an axial vector with the molecule, the observations can be explained. Other recent experiments, among them null experiments showing no CISS related magnetoresistance can be explained using our framework. The physical interpretation is, that the polar electrical polarization of the molecule cannot play a direct role, while the axial magnetic polarization vector operator is a much more realistic candidate. This vector plays an important role in the creation of a magnetic moment in the interface between molecule and metallic lead.

cond-mat.mes-hall↗

arXiv2025

Influence of chemical ordering on magnetocrystalline anisotropy and magnetoelastic properties in Weyl magnetic semimetal Co2MnGa thin films

The magnetic anisotropy and magnetoelastic properties of the magnetic Weyl semimetal Co2MnGa were investigated in the Co2MnGa thin films with different chemical orderings. Their properties change, in line with the increase in the contents of the highly-ordered B2 and L21 phases. The most significant changes of both the magnetic anisotropy and the magnetoelastic properties were correlated with the appearance of the L21 ordered phase of Heusler alloy, which is also responsible for topological properties of these compounds. The magnetoelastic properties of L21 ordered Co2MnGa are discussed in comparison with the Co2FexMn1-xSi system with a similar degree of ordering, which has similar crystallographic structure but it is not Weyl semimetal. In particular, significant differences between the magnetoelastic properties of ordered Co2MnGa and Co2MnSi were found. In the case of L21-ordered Co2MnGa, the giant anisotropy of the magnetoelastic properties was observed.

cond-mat.mtrl-sci↗

arXiv2023

Carrier separation in type II quantum dots inserted in (Zn,Mg)Te/ZnSe nanowire

Quantum dots consisting of an axial Zn0.97Mg0.03Te insertion inside a large bandgap Zn0.9Mg0.1Te nanowire cores are fabricated in a molecular beam epitaxy system by employing the vapor-liquid-solid growth mechanism. Additionally, this structure is coated with a thin ZnSe radial shell which forms type II interface with the dot semiconductor. The resulting radial electron-hole separation is evidenced by several distinct effects which occur in the presence of ZnSe shell, including: the optical emission redshift of about 250 meV, a significant decrease of the emission intensity, the increase of the excitonic lifetime by one order of magnitude and the increase of the biexciton binding energy. The type II nanowire quantum dots where electrons and holes are radially separated constitute a promising platform for potential applications in the field of quantum information technology.

cond-mat.mes-hall↗

arXiv2022

Cooperative effect of electrons spin polarization in a hybrid nanostructure of a magnetic thin film with adsorbed chiral molecules studied with non-spin-polarized scanning tunneling microscopy

Polyalanine molecules (PA) with an α-helix conformation gathered recently a lot of interest as the propagation of electrons through the chiral backbone structure comes along with spin polarization of the transmitted electrons. By means of scanning tunneling microscopy and spectroscopy at ambient conditions, PA molecules adsorbed on surfaces of epitaxial magnetic Al2O3/Pt/Au/Co/Au nanostructures with perpendicular anisotropy were studied. Thereby, a correlation between the PA molecules ordering at the surface with the electron tunneling across this hybrid system as a function of the substrate magnetization orientation as well as the coverage density and helicity of the was observed. The highest spin polarization values, P, were found for well-ordered self-assembled monolayers and with a defined chemical coupling of the molecules to the magnetic substrate surface, showing that the current induced spin selectivity is a cooperative effect. Thereby, P deduced from the electron transmission along unoccupied molecular orbitals of the helical molecules is larger as compared to values derived from the occupied molecular orbitals. Apparently, the larger orbital overlap is resulting in a higher electron mobility yielding a higher P value. By switching the magnetization direction of the Co-layer, it was demonstrated that the non-spin-polarized STM can be used to study chiral molecules with a sub-molecular resolution, to detect properties of buried magnetic layers and to detect the spin polarization of the molecules from the change of the magnetoresistance of such hybrid structures.

cond-mat.mes-hall↗