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Measurements of the superconducting upper critical field, H_{c2}, and critical current density, J_c, have been carried out for MgB_2 doped with Ti and/or C in order to explore the problems encountered if these dopants are used to enhance…
A study of an impurity driven phase-transition into a magnetically ordered state in the spin-liquid Haldane chain compound PbNi2V2O8 is presented. Both, macroscopic magnetization as well as 51V nuclear magnetic resonance (NMR) measurements…
It is widely believed that the origin of a significant cause for the voltage and capacity fading observed in lithium (Li)-ion batteries is related to structural modifications occurring in the cathode material during the Li-ion…
Ab initio density-functional theory study suggests that pillared Li-dispersed boron carbide nanotubes is capable of storing hydrogen with a mass density higher than 6.0 weight% and a volumetric density higher than 45 g/L. The boron…
We address the long-standing question of the nature of oxygen vacancies in strontium titanate, using a combination of density functional theory and dynamical mean-field theory (DFT+DMFT) to investigate in particular the effect of…
Fe-sheathed MgB2 tapes with cheap stearic acid, Mg stearate and Zn stearate doping were prepared through the in situ powder-in-tube method. It is found that Jc, Hirr, and Hc2 were significantly enhanced by doping. Compared to the pure…
Determining the types and concentrations of vacancies present in intentionally doped GaN is a notoriously difficult and long-debated problem. Here we use an unconventional approach, based on thermal transport modeling, to determine the…
A review of current developments in the study of chemical doping effect on the superconducting properties of MgB2 wires and tapes is presented, based on the known literature data and our own results. The critical current density of MgB2 can…
Very recently, a report on possible room-temperature superconductivity in N-doped lutetium hydrides near 1 GPa pressure has drawn lots of attentions. To date, the superconductivity is not confirmed under relatively low pressure in…
The behaviors of hydrogen (H) in MAX phase material Ti3SiC2 have been investigated using first-principles method. We show that a single H atom prefers to stay 1.01 {\AA} down of the Si vacancy with solution energy of about -4.07 eV,…
The physics of doping a Mott insulator is investigated in the presence of a solid-vacuum interface. Using the embedding approach for dynamical mean field theory we show that the change in surface spectral evolution in a doped Mott insulator…
Structure, transport and magnetic properties have been investigated for layered NaCo1-xMnxO2 materials. With the increase of Mn-doping amount, measurements of x-ray diffraction indicate that the in-plane lattice parameter a decreases…
We present first principles calculations of the dynamic susceptibility in strained and doped ferromagnetic MnBi using time-dependent density functional theory. In spite of being a metal, MnBi exhibits signatures of strong correlation and a…
The modifications in the electronic structure of Ni_{2+x}Mn_{1-x}Ga by Ni doping have been studied using full potential linearized augmented plane wave method and ultra-violet photoemission spectroscopy. Ni 3d related electron states appear…
The doping and temperature dependence of the thermodynamic properties in cuprate superconductors is studied based on the kinetic energy driven superconducting mechanism. By considering the interplay between the superconducting gap and…
We perform hybrid-density functional calculations to investigate the charged defect formation energy of native point defects in $Mg_2 Si$, $Mg_2 Sn$, and their solid solutions. The band gap correction by hybrid-density functional is found…
Oxygen defective cerium oxides exhibits a non classical giant electromechanical response that is superior to lead based electrostrictors. In this work, we report the key role of acceptor dopants, with different size and valence Mg2+, Sc3+,…
The strong electron-electron interaction in transition metal dichalcogenides (TMDs) gives rise to phenomena such as strong exciton and trion binding and excitonic condensation, as well as large negative exchange and correlation…
Doping effect of diamond nanoparticles on the superconducting properties of MgB2 bulk material has been studied. It is found that the superconducting transition temperature Tc of MgB2 is suppressed by the diamond-doping, however, the…
We have developed a simple and straightforward way to realize controlled post-doping towards 2D transition metal dichalcogenides (TMDs). The key idea is to use low-kinetic energy dopant beams and a high-flux chalcogen beam at the same time,…