Searcharxiv⌕ Search

arXiv subjects

Misa Nozaki

Publications and source records attributed to Misa Nozaki.

5 recordsLinked to original sources
arXiv2026

Magnetoresistance in chiral systems driven by inter-band spin-orbit coupling

Chiral-induced spin selectivity (CISS), in which electrons transmitted through nonmagnetic chiral materials exhibit strong spin-dependent transport, has attracted growing interest for spintronic applications. However, a quantitative understanding of CISS remains elusive, partly because most previous studies rely on single-band models. In this work, we theoretically investigate multi-band effects on magnetoresistance (MR)-CISS, which is typically observed in experiments using magnetic conductive atomic force microscopy. To evaluate the spin polarization in MR-CISS, we simulate the nonequilibrium steady-state current using the Gorini-Kossakowski-Sudarshan-Lindblad master equation. We find that spin polarization exceeding 25% can be achieved for realistic inter-band spin-orbit coupling strengths in the presence of on-site Coulomb interactions. These findings highlight the crucial role of inter-band spin-orbit coupling in the mechanism of CISS.

cond-mat.mes-hall↗
arXiv2026

Femtosecond concerted rotation of molecules on a 2D material interface

Interfaces between molecules and 2D materials exhibit energy-driven functionalities, wherein charge transfer directs molecular motion. Unlike equilibrium systems, where molecular assemblies settle into static configurations, continuous energy input can drive transient, collective molecular rearrangements. Here, we reveal ultrafast spectroscopic fingerprints of a collective rotational response of molecules on a 2D material following photoexcitation. Our results suggest that photoinduced charge transfer reshapes the interfacial energy potential, giving rise to macroscopic, unidirectional molecular rotation and the formation of a homochiral molecular arrangement. Using a multiplexed ultrafast photoemission spectroscopy approach, we simultaneously track, electronic states, atomic positions, and orbital wavefunctions with femtosecond and sub-ångström resolution. Multimodal valence and core electron emission analysis disentangles the intertwined electronic-structural dynamics of the molecule and the 2D material, revealing the dynamic modulation of charge distribution and intermolecular forces that drive collective molecular motion. Our findings open a pathway for designing energy-driven molecular systems with tunable interfacial dynamics, with potential applications in chiral engineering and active matter systems.

cond-mat.mtrl-sci↗
arXiv2024

Photoemission orbital tomography based on tight-binding approach: method and application to $π$-conjugated molecules

Conventional photoemission orbital tomography based on Fourier iterative method enables us to extract a projected two-dimensional (2D) molecular orbital from a 2D photoelectron momentum map (PMM) of planar $π$-conjugated molecules in a single-orientation system, while not in a multi-orientation system. In this work, we demonstrate photoemission orbital tomography for $π$-conjugated molecules with a tight-binding ansatz (linear combination of atomic orbitals). We analyze 2D PMMs of single-orientation pentacene/Ag(110) and multi-orientation 3,4,9,10-perylenetetracarboxylic dianhydride/Ag(110) and reproduce their three-dimensional highest occupied molecular orbitals. We demonstrate that the PhaseLift algorithm can be used to analyze PMM including experimental or theoretical uncertainties. With the 2D PMM for pentacene, we simultaneously optimized the structure and the molecular orbital. The present approach enables us to extract the three-dimensional orbitals and structures of existing materials.

cond-mat.mtrl-sci↗
arXiv2024

A computational method for angle-resolved photoemission spectra from repeated-slab band structure calculations

A versatile method for angle-resolved photoemission spectra (ARPES) calculations is reported within the one-step model of photoemission. The initial states are obtained from a repeated-slab calculation using the projector-augmented wave (PAW) method. ARPES final states are constructed by matching the repeated-slab eigenstates of positive energy with free electron states that satisfy the time-reversed low-energy electron diffraction boundary conditions. Nonphysical solutions of the matching equations, which do not respect the flux conservation, are discarded. The method is applied to surface-normal photoemission from graphene as a function of photon energy from threshold up to 100 eV. The results are compared with independently performed multiple scattering calculations and very good agreement is obtained, provided that the photoemission matrix elements are computed with all-electron waves reconstructed from the PAW pseudo-waves. However, if the pseudo-waves are used directly, the relative intensity between $σ$- and $π$-band emission is wrong by an order of magnitude. The graphene ARPES intensity has a strong photon energy dependence including resonances. The normal emission spectrum from the $π$-band shows a hitherto unreported, sharp resonance at a photon energy of 31 eV. The resonance is due to a 2$D$ interband transitions and highlights the importance of matrix element effects beyond the final state plane-wave approximation.

cond-mat.mtrl-sci↗