2019/04/30 by Xiqiao Wang, Jonathan Wyrick, Wang, Xiqiao +18
Engineering · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum Physics (quant-ph) #Quantum and electron transport phenomena #Surface and Thin Film Phenomena #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.48550/arxiv.1905.00132
openalex publication_date 2019/04/30 · arxiv created 2019/07/27 · arxiv updated 2019/07/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Atomically precise donor-based quantum devices are a promising candidate for scalable solid-state quantum computing. Atomically precise design and implementation of the tunnel coupling in these devices is essential to realize gate-tunable exchange coupling, and electron spin initialization and readout. Current efforts in atomically precise lithography have enabled deterministic placement of single dopant atoms into the Si lattice with sub-nm precision. However, critical challenges in atomically precise fabrication have meant systematic, atomic-scale control of the tunneling coupling has not been demonstrated. Here using a room-temperature grown locking layer and precise control over the entire atomic-scale fabrication process, we demonstrate atomic-scale control of the tunnel coupling in atomically precise single-electron transistors (SETs). Using the naturally occurring Si (100) 2x1 surface reconstruction lattice as an atomically-precise ruler, we systematically vary the number of lattice counts within the tunnel junction gaps and demonstrate exponential scaling of the tunneling resistance at the atomic limit. Using low-temperature transport measurements, we characterize the tunnel coupling asymmetry in a pair of nominally identical tunnel gaps that results from atomic-scale variation in the tunnel junction and show a resistance difference of four that corresponds to half a dimer row pitch difference in the effective tunnel gap distances - the intrinsic limit of hydrogen lithography precision on Si (100) 2x1 surfaces. Our results demonstrate the key capability to do atom-scale design and engineering of the tunnel coupling necessary for solid-state quantum computing and analog quantum simulation.