相关论文: Native point defects in $Ti_3GeC_2$ and $Ti_2GeC$

The similarity of the electronic structures of NaFeAs and other Fe pnictides has been demonstrated on the basis of first-principle calculations. The global double-degeneracy of electronic bands along X-M and R-A direction indicates the…

We provide direct evidence that the broad Z$_{1/2}$ peak, commonly observed by conventional DLTS in as-grown and at high concentrations in radiation damaged $4H$-SiC, has two components, namely Z$_{1}$ and Z$_{2}$, with activation energies…

Point-contact Andreev reflection spectroscopy at low temperatures and high magnetic fields has been performed on a noncentrosymmetric La$_3$Se$_4$ superconductor with a critical temperature $T_c$ = 8 K. Two superconducting energy gaps…

We have studied the variation of Tc with charge density and lattice parameters in Mg1-xAlxB2 superconducting samples at low Al doping x<8%. We show that high Tc occurs where the chemical potential is tuned at a "superconducting shape…

The impact of Ge vacancies on the low-temperature lattice dynamics of single-crystalline GeTe was investigated through a comparative study of two off-stoichiometric samples: Ge$_{0.8}$Te (S$_1$) and Ge$_{0.88}$Te (S$_2$). X-ray diffraction…

We report an optical spectroscopy study on the single crystal of Na$_2$Ti$_2$As$_2$O, a sister compound of superconductor BaTi$_2$Sb$_2$O. The study reveals unexpectedly two density wave phase transitions. The first transition at 320 K…

The thermal conductivity of borocarbide superconductor LuNi_2B_2C was measured down to 70 mK (T_c/200) in a magnetic field perpendicular to the heat current from H = 0 to above H_c2 = 7 T. As soon as vortices enter the sample, the…

The influence of edge vacancies on the working ability of the planar graphene tunnel field-effect transistor (TFET) is studied at various concentrations and distributions (normal, uniform, periodic) of defects. All calculations are…

Anatase TiO2 is an indirect band-gap material with large degree of sub-stoichiometry, selective excitation of its native defect reveals polychromatic emission in blue, green and red spectral regions due to self trapped excitons and…

A zero-gap state (ZGS) has been found in a bulk system of two-dimensional organic conductor, $\alpha$-(BEDT-TTF)$_2$I$_3$ salt which consists of four sites of donor molecules in a unit cell. In the present paper, the characteristic of the…

The binary Bi-chalchogenides, Bi2Ch3, are widely regarded as model examples of a recently discovered new form of quantum matter, the three-dimensional topological insulator (TI) [1-4]. These compounds host a single spin-helical surface…

Enhanced conductivity at ferroelectric domain walls in BiFeO$_3$ has been widely observed, yet the microscopic origins of this effect, including electronic contributions from domain-wall defects, are incompletely understood at the atomistic…

Competition between collective states like charge density wave and superconductivity is played out in some of the transition metal dichalcogenides unencumbered by the spin degrees of freedom. Although 2H-NbSe$_2$ has received much less…

Thermodynamics and kinetics of Li, Na, and Mg storage in Ge is studied ab initio. The most stable configurations can consist of tetrahedral, substitutional, or a combination of the two types of sites. In the dilute limit, Li, Na prefer…

The defect stability in a prototypical perovskite oxide superlattice consisting of SrTiO$_3$ and PbTiO$_3$ (STO/PTO) is determined using first principles density functional theory calculations. Specifically, the oxygen vacancy formation…

We report the direct observation in real space of the charge density wave (CDW) phase transition in pristine 2H-NbSe2 using atomic-resolution scanning tunneling microscopy (STM). We find that static CDW order is established in nanoscale…

We present a comprehensive study of the vacancy in bulk silicon in all its charge states from 2+ to 2-, using a supercell approach within plane-wave density-functional theory, and systematically quantify the various contributions to the…

Thermal decomposition of metastable fcc-(Ti,Al)Nx limits the lifetime of coated components. While energetic decomposition aspects can be modelled reliably, the inherent variability of chemical environment-dependent diffusion activation…

Hexagonally deformed Fermi surfaces and strong nesting, found in topological insulators (TIs) such as $Bi_2Se_3$ and $Bi_2Te_3$, have led to several predictions of the existence of Density Wave order in these systems. Recent evidence for…

Using density functional theory (DFT) calculations, we have systematically investigated the thermodynamic properties and structural stabilities of thorium dioxide (ThO$_2$). Based on the calculated phonon dispersion curves, we calculate the…