Related papers: The two gap transitions in Ge$_{1-x}$Sn$_x$: effec…
Ge_(1-x)Sn_x alloys have proved difficult to form at large x, contrary to what happens with other group IV semiconductor combinations. However, at low x they are typical examples of well-behaved substitutional compounds, which is desirable…
We calculate the electronic structure of germanium-tin (Ge$_{1-x}$Sn$_{x}$) binary alloys for $0 \leq x \leq 1$ using density functional theory (DFT). Relaxed alloys with semiconducting or semimetallic behaviour as a function of Sn…
Si$_x$Ge$_{1-x-y}$Sn$_y$ ternary alloys are a candidate material system for use in solar cells and other optoelectronic devices. We report on the direct transition energies and structural properties of Ge-rich Si$_x$Ge$_{1-x-y}$Sn$_y$…
We present and compare three distinct atomistic models -- based on first principles and semi-empirical approaches -- of the structural and electronic properties of Ge$_{1-x}$Sn$_{x}$ alloys. Density functional theory calculations…
The local electronic structure of N atoms in a diluted GaAs1-xNx (x=3%) alloy, in view of applications in optoelectronics, is determined for the first time using soft-X-ray absorption (SXA) and emission (SXE). Deviations from crystalline…
Several approaches have been used to investigate the impact of Nitrogen (N) on the electronic structure of GaAs$_{1-x}$N$_{x}$ alloys, however, there is no agreement between theory and experiments about the importance of the different N…
A Gallium interstitial defect (Ga$_{\textrm{i}}$) is thought to be responsible for the spectacular spin-dependent recombination (SDR) in GaAs$_{1-x}$N$_x$ dilute nitride semiconductors. Current understanding associates this defect with two…
Unlike cubic GeSn, which requires a high Sn concentration to undergo an indirect-to-direct bandgap transition, lonsdaleite (2H) germanium is an intrinsic direct-gap semiconductor. We employ first-principles density functional theory to…
The electronic structure of Pb$_{1-x}$Sn$_{x}$Te is studied by using the relativistic Korringa-Kohn-Rostoker Green function method in the framework of density functional theory. For all concentrations $x$, Pb$_{1-x}$Sn$_{x}$Te is a direct…
We present a combined experimental and theoretical analysis of the evolution of the near-band gap electronic and optical properties of Si$_{x}$Ge$_{1-x-y}$Sn$_{y}$ alloys lattice-matched to Ge and GaAs substrates. We perform…
Modification of graphene to open a robust gap in its electronic spectrum is essential for its use in field effect transistors and photochemistry applications. Inspired by recent experimental success in the preparation of homogeneous alloys…
The electronic structure change of NiS$_{2-x}$Se$_x$ as a function of Se concentration $x$ has been studied by Ni $L$-edge X-ray absorption spectroscopy (XAS). The XAS spectra show distinct features in Ni $L_3$ edge, indicating whether the…
Rutile Sn$_{1-x}$Ge$_x$O$_{2}$ alloys are promising materials for high-power electronic applications due to their dopability and tunable ultra-wide band gaps. We use first-principles density functional theory and statistical mechanics to…
Alloying effects by T=Mn,Co,Ni-substitution on FeS$_2$ have been investigated using density-functional calculations. The ferromagnetic alloys Fe$_{1-x}$T$_x$S$_2$ have been investigated for concentrations…
The compositional dependence of the lowest direct and indirect band gaps in $\text{Ge}_{1-y}\text{Sn}_{y}$ has been determined from room-temperature photoluminescence measurements. This technique is particularly attractive for a comparison…
The formation and electronic properties of nitrogen-related defect complexes in $\beta-Ga_2O_3$ are investigated using first-principles calculations. Starting from the energetically favorable $N_{i9}-N_{OI}$ configuration, nitrogen atoms…
Two-dimensional (2D) perovskites show higher stability in comparison to their three-dimensional (3D) counterparts. Therefore, 2D perovskites have invoked remarkable attention in basic understanding of their physical properties and…
Defect energy formation, lattice distortions and electronic structure of cubic In2O3 with Sn, Ga and O impurities were theoretically investigated using density functional theory. Different types of point defects, consisting of 1 to 4 atoms…
We present a spin density functional theory (DFT) study for semiconducting ScN and Mn-substituted ScN. Their structural and magnetic properties have been investigated using the all electrons augmented spherical wave method (ASW) with a…
We investigate the electronic structure and defect properties of Sn- and Ge- doped ZnTe by first-principles calculations within the DFT+$GW$ formalism. We find that $(\text{Sn}_\text{Zn})$ and $(\text{Ge}_\text{Zn})$ introduce isolated…