Related papers: Breaking the doping limit in silicon by deep impur…
Bismuth selenide (Bi2Se3) is a good topological insulator (TI) with its surface band Dirac point inside the bulk bandgap. However, Bi2Se3 films grown by molecular beam epitaxy (MBE) often require tuning of Fermi level near the Dirac point…
Effect of doping of graphene either by Boron (B), Nitrogen (N) or co-doped by B and N is studied using density functional theory. Our extensive band structure and density of states calculations indicate that upon doping by N (electron…
Infrared reflectivity measurements on 122 iron-pnictides reveal the existence of two electronic subsystems. The one gapped due to the spin-density-wave transition in the parent materials, such as EuFe$_2$As$_{2}$, is responsible for…
We study the electronic instabilities of newly predicted Ni-based high-$T_c$ superconducting material La$_2$Ni$_2$Se$_2$O$_3$ based on the random phase approximation. Our calculations on the susceptibility indicate that the collinear…
Intercalated Fe chalcogenide K$_2$Fe$_4$Se$_5$ family exhibits high Tc ($\sim$ 30 K) superconductivity and spin-8 high T$_{\rm N}$ ($\sim$ 560 K) antiferromagnetism (AFM). We present a model Hamiltonian and suggest \textit{Skyrmion…
Chemical doping has recently become a very important strategy to induce superconductivity especially in complex compounds. Distinguished examples include Ba-doped La$_2$CuO$_4$ (the first high temperature superconductor), K-doped BaBiO$_3$,…
Properties of transition metal (TM) doped single wall (8,0) SiC nanotube is investigated using first principles density functional theory as implemented within quantum espresso code. The properties studied are electronic, optical, and…
A series of solid organic acids were used to p-dope carbon nanotubes. The extent of doping is shown to be dependent on the pKa value of the acids. Highly fluorinated carboxylic acids and sulfonic acids are very effective in shifting the…
A two-step doping process, magnetic followed by charge or vice versa, is required to produce insulating massive surface states in topological insulators for many physics and device applications. Using first-principles calculations, we…
We built graphene nanoflakes doped or not with $C$ atoms in the $sp^3$ hybridization or with $Si$ atoms. These nanoflakes are isolated, i.e. are not connected to any object (substrate or junction). We used a modified tight binding method to…
To realize high-temperature operation of Si qubits, deep impurity levels with large confinement energy, which are hardly thermally excited, have been introduced into Si wafers. Group II impurity Zn and group VI impurities S and Se, which…
Two-dimensional transition-metal dichalcogenides (TMDs) have attracted interest as post-Si channel candidates in transistor technology. However, despite their potential benefits, controllably doping TMDs has proven difficult. In this work,…
Recently, LiGa$_5$O$_8$ was identified as a cubic spinel type ultra-wide-band-gap semiconductor with a gap of about 5.36 eV and reported to be unintentionally p-type. Here we present first-principles calculations of the native defects and…
Superconductivity frequently appears by doping compounds that show a collective phase transition. So far, however, this has not been observed in topological materials. Here we report the discovery of superconductivity induced by Ga doping…
We report the effect of 3d metal Cobalt (Co) and Nickel (Ni) doping on the FeTe0.5Se0.5 superconductor with the nominal composition range Fe1-xMxTe0.5Se0.5 (M = Co, Ni and x = 0.00, 0.01 0.02, 0.05, and 0.10). Samples are synthesized…
We investigate the effect of a non-magnetic donor impurity located at the surface of the SnTe topological crystalline insulator. In particular, the changes on the surface states due to a Sb impurity atom are analyzed by means of ab initio…
Over the last few years, group IV hexagonal-diamond type crystals have acquired great attention in semiconductor physics thanks to the appearance of novel and very effective growth methods. However, many questions remain unaddressed on…
Several Fe chalcogenide superconductors without hole pockets at the Fermi level display high temperature superconductivity, in apparent contradiction to naive spin fluctuation pairing arguments. Recently, scanning tunneling microscopy…
The experimental realization of high-temperature superconductivity in compressed hydrides H$_3$S and LaH$_{10}$ at high pressures over 150 GPa has aroused great interest in reducing the stabilization pressure of superconducting hydrides.…
Based on a phenomenological model and the Kubo formula, we investigate the superfluid density $\rho_s(T)$ and then the penetration depth $\lambda(T)$ of the iron-based superconductors in the coexistence region of the spin-density-wave(SDW)…