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We study the effect of a shift of the chemical potential level on the tunneling conductance spectra. In the systems with gapped energy spectra, significant chemical-potential dependent distortions of the differential tunneling conductance…

Mesoscale and Nanoscale Physics · Physics 2016-12-21 N. I. Fedotov , S. V. Zaitsev-Zotov

Hybrid functional calculations are presented for defects in LiGaO$_2$ with the fraction of non-local exchange adjusted to reproduce the recently reported exciton gap of 6.0 eV. We study how the defect transition levels of the main native…

Materials Science · Physics 2023-06-21 Klichchupong Dabsamut , Adisak Boonchun , Walter R. L. Lambrecht

Band offsets at semiconductor-oxide interfaces are determined through a scheme based on hybrid density functionals, which incorporate a fraction $\alpha$ of Hartree-Fock exchange. For each bulk component, the fraction $\alpha$ is tuned to…

Materials Science · Physics 2008-09-19 Audrius Alkauskas , Peter Broqvist , Fabien Devynck , Alfredo Pasquarello

The alignment of the Fermi level of a metal electrode within the gap of the highest occupied and lowest unoccupied orbital of a molecule is a key quantity in molecular electronics. Depending on the type of molecule and the interface…

Materials Science · Physics 2015-06-25 Robert Stadler

Semilocal exchange-correlation functionals are the most accurate, realistic and widely used ones to describe the complex many-electron effects of two-dimensional quantum systems. Beyond local density approximation, the generalized gradient…

Materials Science · Physics 2017-04-12 Subrata Jana , Prasanjit samal

We report calculations of the electronic structure of CaB$_6$ using the weighted density approximation (WDA) to density functional theory. We find a semiconducting band structure with a sizable gap, in contrast to local density…

Strongly Correlated Electrons · Physics 2009-11-10 Z. Wu , D. J. Singh , R. E. Cohen

The paper examines local approximation errors of finite difference schemes in electromagnetic analysis. Despite a long history of the subject, several accuracy-related issues have been overlooked and/or remain controversial. For example,…

Computational Physics · Physics 2020-03-05 Igor Tsukerman

The energy band structures caused by self-energy shifting that results in bound energy levels broadening and merging in warm dense aluminum and beryllium are observed. An energy band theory for warm dense matter (WDM) is proposed and a new…

Plasma Physics · Physics 2018-12-21 Chang Gao , Shen Zhang , X. T. He , Wei Kang , Ping Zhang , Mohan Chen , Cong Wang

The band gap is an important parameter of semiconductor materials that influences several functional properties, in particular optical properties. However, a fast and reliable first-principles prediction of band gaps remains a challenging…

Using the GW approximation, we study the electronic structure of the recently synthesized hydrogenated graphene, named graphane. For both conformations, the minimum band gap is found to be direct at the $\Gamma$ point, and it has a value of…

Materials Science · Physics 2015-05-13 S. Lebegue , M. Klintenberg , O. Eriksson , M. I. Katsnelson

We compare the ability of four popular hybrid density functionals (B3LYP, B3PW91, HSE, and PBE0) for predicting band gaps of semiconductors and insulators over a large benchmark set using a consistent methodology. We observe no significant…

Materials Science · Physics 2016-10-07 Alejandro J. Garza , Gustavo E. Scuseria

The modified Becke-Johnson exchange potential combined with local-density approximation correlation (mBJLDA) has recently attracted interest because it provides highly improved band gaps at a very low computational cost. In this work we…

Materials Science · Physics 2022-04-04 Hazem Abu-Farsakh , Abdallah Qteish

We propose a method to decompose the total energy of a supercell containing defects into contributions of individual atoms, using the energy density formalism within density functional theory. The spatial energy density is unique up to a…

Materials Science · Physics 2011-04-20 Min Yu , Dallas R. Trinkle , Richard M. Martin

We develop a computationally efficient scheme to accurately determine finite-temperature band gaps. We here focus on materials belonging to the class ABX3 (A = Rb, Cs; B = Ge, Sn, Pb; and X = F, Cl, Br, I), which includes halide…

Materials Science · Physics 2022-12-13 Haiyuan Wang , Alexey Tal , Thomas Bischoff , Patrick Gono , Alfredo Pasquarello

We study the charge-density wave phase in $\textup{TiSe}_2$ by using first principle calculations. We show that, regardless of the local functional used and as long as the cell parameters are in agreement with the experiment,…

Mesoscale and Nanoscale Physics · Physics 2015-10-28 Raffaello Bianco , Matteo Calandra , Francesco Mauri

Unlike covalent two-dimensional (2D) materials like graphene, 2D metals have non-layered structures due to their non-directional, metallic bonding. While experiments on 2D metals are still scarce and challenging, density-functional theory…

Materials Science · Physics 2023-01-06 Kameyab Raza Abidi , Pekka Koskinen

We present the results of detailed theoretical investigations of changes in local density of total electronic surface states in 2D anisotropic atomic semiconductor lattice in vicinity of impurity atom for a wide range of applied bias…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 V. N. Mantsevich , N. S. Maslova

When described through a plane-wave basis set, the inclusion of exact nonlocal exchange in hybrid functionals gives rise to a singularity, which slows down the convergence with the density of sampled $k$ points in reciprocal space. In this…

Materials Science · Physics 2009-09-10 Peter Broqvist , Audrius Alkauskas , Alfredo Pasquarello

We present a systematic study that clarifies validity and limitation of current hybrid functionals in density functional theory for structural and electronic properties of various semiconductors and insulators. The three hybrid functionals,…

Materials Science · Physics 2015-03-19 Yu-ichiro Matsushita , Kazuma Nakamura , Atsushi Oshiyama

We construct a nonlocal density functional approximation with full exact exchange, while preserving the constraint-satisfaction approach and justified error cancellations of simpler semilocal functionals. This is achieved by interpolating…

Chemical Physics · Physics 2009-11-13 John P. Perdew , Viktor N. Staroverov , Jianmin Tao , Gustavo E. Scuseria