Application of the aperiodic defect model to a negatively charged monovacancy in phosphorene

TL;DR

This paper demonstrates the application of the aperiodic defect model (ADM) to a negatively charged monovacancy in phosphorene, enabling high-accuracy defect calculations without supercell limitations.

Contribution

It introduces the ADM as a new approach for defect modeling that avoids spurious interactions and allows high-level quantum chemistry methods to be used.

Findings

Benchmark formation energy of 0.81 eV for the defect

Excitation energy of 1.95 eV to the lowest singlet state

ADM effectively bridges solid-state physics and molecular quantum chemistry

Abstract

We apply the recently introduced aperiodic defect model (ADM) to a negatively charged monovacancy in a phosphorene monolayer. In contrast to conventional supercell approaches, the ADM treats a single defect embedded in the true non-defective crystalline mean field thereby avoiding spurious defect-defect interactions and the need for charge corrections. At the same time, it effectively reduces the calculation to a fragment, enabling the use of high-level molecular electronic-structure methods. Converging the Hartree-Fock and correlation contributions to the thermodynamic limit yields a benchmark CCSD(T)/POB-TZVP-rev2 formation energy of 0.81 eV for the negatively charged monovacancy in the (5|9) configuration. The excitation energy to the lowest singlet excited state of this defect at the EOM-CCSD/POB-TZVP-rev2 level is found to be 1.95 eV. Overall, the ADM provides a highly promising route towards quantitatively accurate and systematically improvable descriptions of defects in solids and on surfaces, bridging the gap between solid-state physics and molecular quantum chemistry.