Hao-Wen Xu | Searcharxiv

arXiv2026

Chiral-vibration-induced magnetism and circular dichroism in organic molecules

We investigate the vibrational inverse Faraday effect and transient vibrational circular dichroism in benzene, coronene, and methane at the single-molecule level. We combine density-functional tight-binding calculations with damped normal-mode dynamics. Circularly polarized light excites suitable degenerate infrared-active modes, driving chiral nuclear motion that produces effective magnetic moments. Reversing the pump helicity reverses the vibrational chirality and the sign of the transient dichroic response. These results support a writing-readout scheme in which circularly polarized pumping prepares a chiral vibrational state and transient vibrational circular dichroism probes its handedness. We further examine how molecular symmetry shapes the light-induced chiral response across the three molecular systems. This work provides a valuable platform for exploring all-optical control of magnetism and chiroptical probing at the molecular scale.

cond-mat.other↗

arXiv2025

Domain Wall-mediated Interfacial Ferroelectric Switching

Interfacial ferroelectricity offers a promising platform for ultrafast, low-power memory devices. While previous studies have demonstrated the importance of domain wall in polarization switching, the coexistence of various domain wall types and their impact on polarization stability lacks fundamental understanding. By integrating first-principles calculations, machine learning methods, and experimental validations, we show that domain walls connect opposite polarization states and respond to out-of-plane electric field through polarization vector deviation, leading to inhomogeneous interlayer sliding and domain-wall migration. This mechanism bears clear resemblance to that in traditional ferroelectrics. Notably, different domain wall types result in distinct switching behaviors, which play a crucial role in determining the reversibility of polarization switching. We then propose strategies beyond ideal conditions to achieve non-volatile ferroelectric switching, which are supported by our experimental observations. These insights shed light on the microscopic switching mechanism in hexagonal interfacial ferroelectrics, offering guidance for future nanoelectronics applications.

cond-mat.mtrl-sci↗