Carrier transport in layered nanolaminated films

TL;DR

This paper investigates the anisotropic carrier transport in layered Ti₂AlC using ab-initio calculations, revealing the impact of Fermi surface shape and electron-phonon interactions on its electrical properties.

Contribution

It introduces an analytical model linking electronic structure and phonon interactions to carrier transport in layered nanolaminated films, validated by DFT calculations.

Findings

Carrier effective mass is highly anisotropic due to cylindrical Fermi surface.

Strong inter-valley scattering influences in-plane conductivity.

Deformation potential calculated aligns with experimental transport data.

Abstract

Analyzing {\it{ab-initio}} electronic and phonon band structure, temperature-dependent carrier transport in layered Ti$_{2}$AlC is investigated. It is found that cylindrical Fermi surface is the origin of the anisotropic carrier effective mass (infinite effective mass along $c$ axis ) leading to strong anisotropic (insulator along $c$ axis and metallic along the layer) carrier transport in these films. Using electronic and phonon bandstructures, we develop an analytical model of electron-phonon interaction as well as in-plane carrier conductivity originating from strong inter-valley (s$\rightarrow$d) scattering in Ti$_{2}$AlC. We invoke density functional theory to calculate the deformation potential corresponding to acoustic phonon vibration. The calculated deformation potential is in well agreement with the extracted deformation potential value from the transport data. Extracted deformation potential will be useful for prediction of transport quantities for application of these metals at elevated temperatures.