arXiv subjects

Namgee Cho

Publications and source records attributed to Namgee Cho.

3 recordsLinked to original sources

arXiv2026

Bridging steady-state and time-domain descriptions of molecular electron transport

Electron transmission from an input electrode, through a molecular system, to an output electrode has been widely studied using the steady-state non-equilibrium Green's function (NEGF) method. Recently, the wave packet method, which provides access to the transient dynamics of electrons as well as internal molecular degrees of freedom, has been employed to investigate enantiospecific electron transport through chiral molecules. In this work, we derive the quantitative relation between the transmission of a finite-size wave packet and the energy-resolved NEGF transmission, showing that the former corresponds to a spectral average of the latter weighted by the wave packet energy distribution. Exploiting this correspondence, we construct non-Gaussian auxiliary wave packets whose spectral weight encodes the Landauer energy-window, allowing current-voltage characteristics to be obtained directly from time propagation. We further show that the correspondence extends to spin-resolved transport in a spin-phonon model of chirality-induced spin selectivity.

cond-mat.mes-hall↗

arXiv2025

Chirality-Induced Orbital Selectivity through Linear-Orbital Coupling

We present a three-dimensional continuum model of electron transmission through a chiral electrostatic potential and show that it gives rise to chirality-induced orbital selectivity. In this model, electron transmittance depends strongly on the incident orbital angular momentum (OAM) associated with its transverse motion, and the selectivity reverses when the potential's handedness is inverted. The effect originates from a coupling between axial linear momentum and OAM mediated by the helical spatial dependence of the potential. For DNA-scale geometric parameters, this linear-orbital coupling produces sizable orbital selectivity, which remains robust to static and dynamic disorder, and increases with the length of chiral regions. Although bare spin-orbit coupling in the chiral potential considered here is too weak to generate considerable spin dynamics, spin-OAM correlations in the electrodes allow the same orbital selective mechanism to induce appreciable spin selectivity. These results identify orbital dynamics as an important contributor to electron transport in chiral systems.

cond-mat.mes-hall↗

arXiv2023

Systematic coarse-graining of environments for the non-perturbative simulation of open quantum systems

Conducting precise electronic-vibrational dynamics simulations of molecular systems poses significant challenges when dealing with realistic environments composed of numerous vibrational modes. Here, we introduce a technique for the construction of effective phonon spectral densities that capture accurately open system dynamics over a finite time interval of interest. When combined with existing non-perturbative simulation tools, our approach can reduce significantly the computational costs associated with many-body open system dynamics.

quant-ph↗