Intrinsic breakdown strength: theoretical derivation and first-principles calculations

TL;DR

This paper derives a theoretical model linking intrinsic breakdown strength to the maximum electron density of states and uses first-principles calculations to show that DOS_max, not band gap, governs dielectric strength, with dimensional effects influencing F_bd.

Contribution

The work introduces a simplified analytical model relating F_bd to DOS_max and demonstrates its validity through first-principles calculations across various materials.

Findings

F_bd linearly correlates with DOS_max, not band gap.

Monolayers exhibit higher F_bd due to reduced screening.

The model provides physical insights for high-power dielectric materials.

Abstract

Intrinsic breakdown strength (F_bd), as the theoretical upper limit of electric field strength that a material can sustain, plays important roles in determining dielectric and safety performance. The well accepted concept is that a larger band gap (E_g) often leads to a larger intrinsic breakdown strength. In this work, we analytically derive a simplified model of F_bd, showing a linear relationship between F_bd and the maximum electron density of states (DOS_max) within the energy range spanning from the conduction band minimum (CBM) to CBM+E_g. Using the Wannier interpolation technique to reduce the cost of calculating the F_bd for various three- and two-dimensional materials, we find that the calculated F_bd did not show any simple relationship with band gap, but it behaves linearly with the DOS_max, consistent with our theoretical derivation. Our work shows that the DOS_max is more fundamental than the band gap value in determining the F_bd, thus providing useful physical insights into the intrinsic dielectric breakdown strength and opening directions for improving high-power devices. The dimensional effects on F_bd has also been revealed that monolayers tend to have larger F_bd due to reduced screening effects.