High-frequency complex impedance analysis of the two-dimensional semiconducting MXene-$Ti_2CO_2$

TL;DR

This paper presents an ab-initio study of the high-frequency ac-transport properties of the semiconducting MXene-$Ti_2CO_2$, revealing detailed insights into electron mobility and conductivity beyond room temperature up to terahertz frequencies.

Contribution

It introduces a first-principles transport model for analyzing ac-electronic properties of MXenes, surpassing traditional models like Drude's and incorporating various phonon scattering mechanisms.

Findings

Carrier mobility and conductivity vary significantly with frequency and temperature.

The model accurately predicts ac-transport behavior without experimental input.

Insights into scattering mechanisms affecting electron transport in MXenes.

Abstract

The two-dimensional compound group of MXenes, which exhibit unique optical, electrical, chemical, and mechanical properties, are an exceptional class of transition metal carbides and nitrides. In addition to traditional applications in Li-S, Li-ion batteries, conductive electrodes, hydrogen storage, and fuel cells, the low lattice thermal conductivity coupled with high electron mobility in the semiconducting oxygen-functionalized MXene-$Ti_2CO_2$ has led to the recent interests in high-performance thermoelectric and nanoelectronic devices. Apart from the above dc-transport applications, it is crucial to also understand ac-transport across them, given the growing interest in applications surrounding wireless communications and transparent conductors. In this work, we investigate using our recently developed $ab~initio$ transport model, the real and imaginary components of electron mobility and conductivity to conclusively depict carrier transport beyond the room temperature for frequency ranges upto the terahertz range. We also contrast the carrier mobility and conductivity with respect to the Drude's model to depict its inaccuracies for a meaningful comparison with experiments. Our calculations show the effect of acoustic deformation potential scattering, piezoelectric scattering, and polar optical phonon scattering mechanisms. Without relying on experimental data, our model requires inputs calculated from first principles using density functional theory. Our results set the stage for providing ab-initio based ac-transport calculations given the current research on MXenes for high frequency applications.