Curator's Take
AI Commentary
This article demonstrates that Landau‑Zener‑Stückelberg‑Majorana interference can be harnessed for fully electrical, non‑resonant manipulation of individual atomic spins, turning a Ti‑Ti‑Fe trimer on MgO into a fast, low‑decoherence qubit platform. By engineering avoided crossings with combined magnetic fields and bias voltage, the authors achieve remote spin control via the Fe atom’s stray field, sidestepping the disruptive tunneling currents that have limited previous ESR‑STM approaches. The work provides a concrete pathway toward scalable atom‑based quantum processors by showing how quantum interference can replace microwave driving for rapid, coherent gate operations.
— Mark Eatherly
Summary
We propose a protocol for the non-resonant electric control of quantum states in atomic-scale spin systems using Landau-Zener-Stückelberg-Majorana (LZSM) interferometry. We focus on a Ti-Ti-Fe trimer on a thin MgO layer, a platform that has recently emerged as a promising candidate for qubit realization using electron spin resonance combined with scanning tunneling microscopy (ESR-STM). We first analyze a Ti dimer in the absence of the Fe atom and show, through a detailed spectroscopic study, that avoided level crossings can be engineered by combining the in-plane component of the external magnetic field, the tip magnetic field, and the applied bias voltage, which allows the system to be tuned electrically through these crossings. Based on this, we develop LZSM protocols for coherent state control in the dimer using non-resonant LZSM-STM. We then consider the full trimer, where the Fe atom generates a local magnetic field at the remote Ti atom, enabling non-local spin control. We show that this remote and non-resonant manipulation reduces unwanted effects associated with tunneling electrons and enables quantum operations on short timescales. Our results show that quantum interference can be used as a resource for electrically driven, non-resonant, and non-local spin control in atomic-scale systems. This approach enables fast quantum operations while mitigating decoherence, offering a promising route toward scalable atom-based qubit architectures.