First-Principles Simulations of Inelastic Electron Tunneling Spectroscopyof Molecular Junctions

A generalized Green's function theory is developed to simulate the inelastic electron tunneling spectroscopy (IETS) of molecular junctions. It has been applied to a realistic molecular junction with an octanedithiolate embedded between two gold contacts in combination with the hybrid density functional theory calculations. The calculated spectra are in excellent agreement with recent experimental results. Strong temperature dependence of the experimental IETS spectra is also reproduced. It is shown that the IETS is extremely sensitive to the intra-molecular conformation and to the molecule-metal contact geometry

Hidden persistent spin texture in bulk crystals

Exploring hidden effects that have been overlooked given the nominal global crystal symmetry but are indeed visible in solid-state materials has been a fascinating subject of research recently. Here, we introduce a novel type of hidden persistent spin texture (HPST) in nonmagnetic bulk crystals consisting of a pair of real-space sectors. In these crystals, the doubly degenerate bands formed in the momentum space can exhibit a uniform spin configuration with opposite spin orientations, which are spatially separated in the paired sectors. Interestingly, we find that such a type of spin texture can be hidden in both centrosymmetric and non-centrosymmetric materials. We further demonstrate the important role of nonsymmorphic twofold screw-rotational symmetry played in the formation of HPST. Moreover, two representative material examples, i.e., centrosymmetric WSe$_2$ and noncentrosymmetric BaBi$_4$O$_7$, are identified to show HPST via first-principles calculations. Our finding thus not only opens new perspectives for hidden spin polarization research but also significantly broadens the range of materials towards spintronics applications.Comment: 5 pages, 3 figure