Enhancing Electron Coherence via Quantum Phonon Confinement in Atomically Thin Nb3SiTe6

TL;DR

This paper demonstrates that thinning Nb3SiTe6 to atomic layers enhances electron coherence by suppressing electron-phonon interactions, revealing quantum confinement effects in 2D transition metal chalcogenides.

Contribution

It reports the first observation of enhanced weak-antilocalization in atomically thin Nb3SiTe6, linking quantum confinement to suppressed electron-phonon interactions.

Findings

Enhanced weak-antilocalization observed in ultrathin Nb3SiTe6

Suppression of electron-phonon interactions in 2D limit

Confirmation of quantum confinement effects in 2D TMCs

Abstract

The extraordinary properties of two dimensional (2D) materials, such as the extremely high carrier mobility in graphene and the large direct band gaps in transition metal dichalcogenides MX2 (M = Mo or W, X = S, Se) monolayers, highlight the crucial role quantum confinement can have in producing a wide spectrum of technologically important electronic properties. Currently one of the highest priorities in the field is to search for new 2D crystalline systems with structural and electronic properties that can be exploited for device development. In this letter, we report on the unusual quantum transport properties of the 2D ternary transition metal chalcogenide - Nb3SiTe6. We show that the micaceous nature of Nb3SiTe6 allows it to be thinned down to one-unit-cell thick 2D crystals using microexfoliation technique. When the thickness of Nb3SiTe6 crystal is reduced below a few unit-cells thickness, we observed an unexpected, enhanced weak-antilocalization signature in magnetotransport. This finding provides solid evidence for the long-predicted suppression of electron-phonon interaction caused by the crossover of phonon spectrum from 3D to 2D.