On the role of the nonlocal Hartree-Fock exchange in ab initio quantum transport: Hydrogen in Platinum nanocontacts revisited

TL;DR

This paper introduces a method to improve quantum transport calculations by incorporating nonlocal Hartree-Fock exchange, reducing overestimated conductance in hydrogen-platinum nanocontacts, aligning results with advanced theories.

Contribution

It presents a practical approach to include nonlocal exchange in DFT for quantum transport, addressing overestimation issues and revisiting hydrogen in platinum nanocontacts.

Findings

Conductance decreases with nonlocal exchange inclusion.

Results align with Time-Dependent Current-Density-Functional Theory.

Warns against claims of perfect transparency in hydrogen-platinum contacts.

Abstract

We propose a practical way to overcome the ubiquitous problem of the overestimation of the zero-bias and zero-temperature conductance, which is associated to the use of local approximations to the exchange-correlation functional in Density-Functional Theory when applied to quantum transport. This is done through partial substitution of the local exchange term in the functional by the nonlocal Hartree-Fock exchange. As a non-trivial example of this effect we revisit the smallest molecular bridge studied so far: a Hydrogen molecule placed in between Platinum nanocontacts. When applied to this system the value of the conductance diminishes as compared to the local-exchange-only value, which is in close agreement with results predicted from Time-Dependent Current-Density-Functional Theory. Our results issue a warning message on recent claims of perfect transparency of a Hydrogen molecule in Platinum nanocontacts.