Ronaldo Rodrigues Pela

Comparing LDA-1/2, HSE03, HSE06 and G 0 W 0 approaches for band gap calculations of alloys

It has long been known that the local density approximation and the generalized gradient approximation do not furnish reliable band gaps, and one needs to go beyond these approximations to reliably describe these properties. Among alternatives are the use of hybrid functionals (HSE03 and HSE06 being popular), the GW approximation or the recently proposed LDA-1/2 method. In this work, we compare rigorously the performance of these four methods in describing the band gaps of alloys, employing the generalized quasi-chemical approach to treat the disorder of the alloy and to obtain judiciously the band gap for the entire compositional range. Zincblende InGaAs and InGaN were chosen as prototypes due to their importance in optoelectronic applications. The comparison between these four approaches was guided both by the agreement between the predicted band gap and the experimental one, and by the demanded computational effort (time and memory). We observed that the HSE06 method provided the most accurate results (in comparison with experiments), whereas, surprisingly, the LDA-1/2 method gave the best compromise between accuracy and computational resources. Due to its low computational cost and good accuracy, we decided to double the supercell used to describe the alloys, and employing LDA-1/2 we observed that the bowing parameter changed remarkably, only agreeing with the measured one for the larger supercell, where LDA-1/2 plays an important role.

Probing the LDA-1/2 method as a starting point forG0W0calculations

Employing the

The LDA-1/2 technique: Recent developments

G_0W_0

General procedure for the calculation of accurate defect excitation energies from DFT-1/2 band structures: The case of the NV− center in diamond

approximation of Hedins

Influence of structure and thermodynamic stability on electronic properties of two-dimensional SiC, SiGe, and GeC alloys

GW

Combined LDA and LDA-1/2 method to obtain defect formation energies in large silicon supercells

approach one can obtain quasi-particle energies of extended systems and molecules with good accuracy. However, for many materials, semi-local exchange-correlation functionals are unsatisfactory starting points for

Fast and accurate approximate quasiparticle band structure calculations of ZnO, CdO, and MgO polymorphs

G_0W_0

Charge transition levels of Mn-doped Si calculated with the GGA-1/2 method

calculations. Hybrid functionals often improve upon them, but at a substantially higher computational cost. As an alternative, we suggest the LDA-1/2 method, which provides reasonable band gaps, without being computationally involved. In this work, we systematically compare 3 starting points for

Ab initio predictions of the stability and structural properties of zincblende (III,TM)V magnetic semiconductor alloys

G_0W_0

Kinetic study of α-BZN crystallization obtained from chemical method

: LDA, PBE0, and LDA-1/2. A selection of solids is chosen for this benchmark: C, Si, SiC, AlP, LiF, MgO, Ne, Ar, GaN, GaAs, CdS, ZnS, and ZnO. We demonstrate that LDA-1/2 is a good starting point in most cases, reducing the mean absolute error of band gaps by 50% when compared to the other 2 functionals.