Phase-change materials, 1/ f noise, and phase synchrony

In this article, we study 1/f^γ,γ≈1 electrical noise in amorphous phase-change materials. Given the relevance of noise in recent applications, it is necessary to gain a deeper perspective on its nature in phase-change semiconductors, a promising class of materials. Electron conduction is envisaged in terms of an envelope function and a field-dependent Bloch wave function; the electron transport across the structure is modeled as driven phase oscillators under a weak field and obeys a Kuramoto-type equation. Its solutions naturally divide into a phase-synchronized group and phase-desynchronized oscillators. The former is comprised by long-lived pairs or aggregates and are responsible for 1/f,γ=1 noise. We identify the dividing frequency between γ=1 noise and γ≠1 noise. The phase-desynchronized carriers generate γ≠1 noise and are single carriers, not aggregates, and are short-lived. We apply our analysis to recent experiments.