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
Nguyen T. N. Ha, L. Rasabathina, O. Hellwig, A. Sharma, G. Salvan, S. Yochelis, Y. Paltiel, L. T. Baczewski, C. Tegenkamp
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.
We present a theoretical study, based on density functional theory and tight binding modeling, of the electronic structure and spin transport properties of silicon nanoparticles with adsorbed bismuth atoms. We find the bismuth atoms to form clusters separated by quantum tunnel barriers. We predict strong spin filtering by these nanostructures in the high conductance regime when the source and drain leads are connected to the same bismuth cluster and in the low conductance regime when the source and drain leads are connected to different bismuth clusters. We relate the spin filtering to a symme…
Dirac point resonances due to atoms and molecules adsorbed on graphene and transport gaps and conductance quantization in graphene nanoribbons with covalently bonded adsorbates
Electron Delocalization versus Emission Coherence of Quantum Dot Superlattices
National Gravitation Laboratory, MOE Key Laboratory of Fundamental Physical Quantities Measurement, and School of Physics, Huazhong University of Science and Technology（华中科技大学物理学院，引力教育部重点实验室，国家引力实验室）；Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology（华中科技大学物理学院，武汉光电国家研究中心）；Yunnan Key Laboratory of Ⅲ-Ⅴ Infrared Detectors, Kunming Institute of Physics（昆明物理研究所，云南省Ⅲ-Ⅴ族红外探测器重点实验室）
Coexistence of Ferromagnetic and Overscreened Kondo Effects in a Single Molecule
Empa – Swiss Federal Laboratories for Materials Science and Technology（瑞士联邦材料科技研究院）；Delft University of Technology（代尔夫特理工大学）；Kavli Institute of Nanoscience, Delft University of Technology（代尔夫特理工大学卡弗里纳米科学研究所）；Karlsruhe Institute of Technology（卡尔斯鲁厄理工学院）；University of Bern（伯尔尼大学）；Universidad de Alicante（阿利坎特大学）
Topological phase in magnetic materials yields a quantized contribution to the Hall effect known as the topological Hall effect, which is often caused by skyrmions, with each skyrmion creating a magnetic flux quantum h/e. The control and understanding of topological properties in nanostructured materials is the subject of immense interest for both fundamental science and technological applications, especially in spintronics. In this work, the electron-transport properties and spin structure of exchange-coupled cobalt nanoparticles with an average particle size of 13.7 nm are studied experiment…
