Publications by Hannu-Pekka Komsa

Finite-Size Supercell Correction for Charged Defects at Surfaces and Interfaces

A finite-size supercell correction scheme is introduced for the formation energy of charged defects at surfaces and interfaces. The scheme combines classical electrostatics with the dielectric profile and the electrostatic potential extracted from the elec ...

American Physical Society2013

Finite-size supercell correction schemes for charged defect calculations

Alfredo Pasquarello, Hannu-Pekka Komsa

Various schemes for correcting the finite-size supercell errors in the case of charged defect calculations are analyzed and their performance for a series of defect systems is compared. We focus on the schemes proposed by Makov and Payne (MP), Freysoldt, N ...

2012

Germanium core-level shifts at Ge/GeO2 interfaces through hybrid functionals

Alfredo Pasquarello, Peter Broqvist, Jan Felix Binder, Hannu-Pekka Komsa

The Ge core-level shift across the Ge/GeO2 interface is determined within semilocal and hybrid density functional schemes. We first assess the accuracy achieved within these theoretical frameworks by comparing calculated and measured core-level shifts for ...

2012

Comparison of vacancy and antisite defects in GaAs and InGaAs through hybrid functionals

Alfredo Pasquarello, Hannu-Pekka Komsa

The formation energies and charge transition levels of vacancy and antisite defects in GaAs and In0.5Ga0.5As are calculated through hybrid density functionals. In As-rich conditions, the As antisite is the most stable defect in both GaAs and InGaAs, except ...

2012

Assessing the accuracy of hybrid functionals in the determination of defect levels: Application to the As antisite in GaAs

Alfredo Pasquarello, Hannu-Pekka Komsa

The accuracy of nonscreened and screened hybrid functionals for the calculation of defect levels within the band gap is assessed for the As antisite in GaAs, the nature of which is well characterized experimentally. A set of functionals differing by the fr ...

2011

Identification of defect levels at InxGa1-xAs/oxide interfaces through hybrid functionals

Alfredo Pasquarello, Hannu-Pekka Komsa

Hybrid density functional calculations and atomistic models are used to study point defects in III-V compounds. We first study dangling-bonds in InxGa1-xAs. In GaAs, the cation dangling-bond levels are found in the upper part of the band gap, but they are ...

Elsevier2011

Alignment of defect levels and band edges through hybrid functionals: Effect of screening in the exchange term

Alfredo Pasquarello, Peter Broqvist, Hannu-Pekka Komsa

We investigate how various treatments of exact exchange affect defect charge transition levels and band edges in hybrid functional schemes for a variety of systems. We distinguish the effects of long-range vs short-range exchange and of local vs nonlocal e ...

2010

Dangling bond charge transition levels in AlAs, GaAs, and InAs

Alfredo Pasquarello, Hannu-Pekka Komsa

Charge transition levels of dangling bonds in III-V semiconductors (AlAs, GaAs, and InAs) are determined via hybrid density-functional calculations. In GaAs, the Ga and As levels are found at 0.28 eV below the conduction band and at 0.16 eV above the valen ...

2010