Probing nanocrystalline grain dynamics in nanodevices

TL;DR

This paper reports the experimental detection of reversible switching in nanocrystalline grains within nanodevices, revealing their dynamic behavior and providing microscopic parameters crucial for understanding device performance.

Contribution

It demonstrates a novel electrical method to observe and analyze nanocrystalline grain dynamics, offering insights not accessible through other techniques.

Findings

Reversible switching of nanocrystalline grains observed in RuO2 nanowires

Extracted microscopic parameters include relaxation times and grain boundary strengths

Method complements high-resolution microscopy for structural dynamics analysis

Abstract

Dynamical structural defects exist naturally in a wide variety of solids. They fluctuate temporally, and hence can deteriorate the performance of many electronic devices. Thus far, the entities of such dynamic objects have been identified to be individual atoms. On the other hand, it is a long-standing question whether a nanocrystalline grain constituted of a large number of atoms can switch, as a whole, reversibly like a dynamical atomic defect (i.e., a two-level system). This is an emergent issue considering the current development of nanodevices with ultralow electrical noise, qubits with long quantum coherence time, and nanoelectromechanical system (NEMS) sensors with ultrahigh resolution. Here we demonstrate experimental observations of dynamic nanocrystalline grains which repeatedly switch between two or more metastable coordinate states. We study temporal resistance fluctuations in thin ruthenium dioxide (RuO2) metal nanowires and extract microscopic parameters including relaxation time scales, mobile grain sizes, and the bonding strengths of nanograin boundaries. Such material parameters are not obtainable by other experimental approaches. When combined with previous in-situ high-resolution transmission electron microscopy (HRTEM), our electrical method can be used to infer rich information about the structural dynamics of a wide variety of nanodevices and new 2D materials.