Wafer-Scale Realization of Sub-Nanometer One-Dimensional Nanowire Arrays via Thermomechanical Epitaxy: A New Platform for Quantum Phenomena Exploration

Yi-Xiang Yang^1*, Jan Schroers¹, Jiunn-Yuan Lin², Chien-Ming Tu³, Chih-Wei Luo³

¹Department of Mechanical Engineering and Materials Science, Yale University, New Haven, USA
²Institute of Physics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
³Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan

* Presenter:Yi-Xiang Yang, email:yi-xiang.yang@yale.edu

The development of low-dimensional quantum materials is intrinsically constrained by the challenges of fabricating ultrathin nanostructures with atomic-level precision, scalability, and crystallographic control. Here, we demonstrate wafer-scale fabrication of vertically aligned nanowire arrays with diameters down to 1 nm (less than five atoms in diameter) and aspect ratios exceeding 5000, in dimensions well beyond the capabilities of existing nanofabrication methods.
Our approach, referred to as thermomechanical epitaxy, involves applying a directional pressure differential between a bulk material feedstock and a rigid nanostructured mold. The pressure gradient induces interface diffusion-driven atomic transport, which enables the epitaxial growth of single-crystalline nanowires into the nanocavities of the mold. Owing to the ubiquity of diffusional mechanisms across a wide range of material classes, this technique opens a very versatile and general avenue for fabricating one-dimensional nanowires from a variety of material phases - including topological materials – that have remained experimentally inaccessible at sub-nanometer dimensional scales.
Notably, the fabricated nanowires exist in the strong quantum confinement regime, where quantum effects are expected to dominate physical behavior. Our work provides a rare platform for exploring quantum phenomena, including the potential realization of Majorana zero modes, in one-dimensional nanostructured systems at sub-nanometer scales, where theoretical predictions have far outpaced experimental capabilities.
We will present experimental evidence across a variety of different material systems, demonstrating their structural fidelity, crystallinity, and preliminary quantum transport characterizations, highlighting the broad potential of thermomechanical epitaxy toward next-generation quantum devices and low-dimensional quantum material discovery.

Keywords: Topological matter, 1D Nanostructures, Majorana zero modes, Thermomechanical epitaxy, Wafer-scale nanofabrication