A5008200238- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Graphene research and applications
- Magnetic properties of thin films
- Theoretical and Computational Physics
- Advancements in Battery Materials
- Heusler alloys: electronic and magnetic properties
- 2D Materials and Applications
- Shape Memory Alloy Transformations
- Quantum chaos and dynamical systems
- Metal and Thin Film Mechanics
- Quantum and electron transport phenomena
- Topological Materials and Phenomena
- Iron-based superconductors research
- Intermetallics and Advanced Alloy Properties
- Advanced Physical and Chemical Molecular Interactions
- Scientific Research and Discoveries
- Electron and X-Ray Spectroscopy Techniques
- Advanced Thermoelectric Materials and Devices
- High-pressure geophysics and materials
- Transition Metal Oxide Nanomaterials
- Rare-earth and actinide compounds
- ZnO doping and properties
- Advanced Memory and Neural Computing
Lappeenranta-Lahti University of Technology
2019-2024
Northeastern University
2020-2024
Universidad del Noreste
2024
Howard University
2024
University of Jyväskylä
2013
Recent discovery of superconductivity in the doped infinite-layer nickelates has renewed interest understanding nature high-temperature more generally. The low-energy electronic structure parent compound NdNiO$_{2}$, role correlations driving superconductivity, and possible relationship betweeen cuprates are still open questions. Here, by comparing LaNiO$_2$ NdNiO$_2$ systematically within a parameter-free density functional framework, all-electron first-principles we reveal Nd 4$f$...
Cobalt is used in Li-ion batteries, but it expensive and could be replaced by nickel to deliver better performance at a lower cost. With this motivation, we discuss how the character of redox orbitals LiNiO$_2$ can ascertained through x-ray Compton scattering measurements combined with parallel first-principles simulations. Our analysis reveals nature hole states Li-doped NiO resulting from hybridization O 2$p$ Ni 3$d$ orbitals. study also gives insight into ferromagnetic ground state...
We have investigated the interplay between magnetic and structural degrees of freedom in elemental Mn. The equilibrium volume is shown to depend critically on interactions Mn atoms. While standard generalized-gradient-approximation underestimates volume, a more accurate treatment effects electronic localization magnetism found solve this longstanding problem. capture well complexity large 58 atoms per unit cell $α$-Mn system for first time, including its charge spin patterns canting spins...
Recent discovery of superconductivity in infinite-layer nickelates has ignited renewed theoretical and experimental interest the role electronic correlations their properties. Here, using first-principles simulations, we show that parent compound nickelate family, LaNiO_{2}, hosts competing low-energy stripe phases, similar to doped cuprates. The states are shown be driven by multiorbital mechanisms Peierls distortions. Our study indicates both strong electron-phonon coupling effects play a...
The strongly constrained and appropriately normed (SCAN) semilocal functional for exchange correlation is deployed to study the ground-state properties of ternary Heusler alloys transforming martensitically. calculations are performed ferromagnetic, ferrimagnetic, antiferromagnetic phases. Comparisons between SCAN generalized gradient approximation (GGA) discussed. We find that yields smaller lattice parameters higher magnetic moments compared GGA corresponding values both austenite...
Bi-based cuprate superconductors are important materials for both fundamental research and applications. As in other cuprates, the superconducting phase Bi compounds lies close to an antiferromagnetic phase. Our density functional theory calculations based on strongly-constrained-and-appropriately-normed exchange correlation ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$ reveal persistence of magnetic moments copper ions oxygen concentrations...
The stability of the nonmodulated martensitic phase, austenitic Fermi surface, and phonon dispersion relations for ferromagnetic ${\mathrm{Ni}}_{2}\mathrm{MnGa}$ are studied using density functional theory. Exchange-correlation effects considered with various degrees precision, starting from simplest local spin approximation (LSDA), then adding corrections within generalized gradient (GGA), finally, including meta-GGA strongly constrained appropriately normed (SCAN) functional. We discuss a...
Abstract Van der Waals (vdW) magnetic materials are comprised of layers atomically thin sheets, making them ideal platforms for studying magnetism at the two-dimensional (2D) limit. These center a host novel types experiments, however, there notably few pathways to directly probe their structure. We confirm order within single crystal NiPS 3 and show it can be accessed with resonant elastic X-ray diffraction along edge vdW planes in carefully grown by detecting structurally forbidden...
We have performed density functional theory calculations of graphene decorated with carbon adatoms, which bind at the bridge site a C--C bond. Earlier studies shown that C adatoms magnetic moments and suggested possibility ferromagnetism high Curie temperature. Here we propose to use gate voltage fine tune from zero $1\phantom{\rule{0.16em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}$ while changing coupling antiferromagnetism again antiferromagnetism. These results are rationalized within Stoner...
We discuss optical properties of layered Lithium Nickel oxide (LiNiO2), which is an attractive cathode material for realizing cobalt-free lithium-ion batteries, within the first-principles density functional theory (DFT) framework. Exchange correlation effects are treated using generalized gradient approximation (GGA) and strongly-constrained-and-appropriately-normed (SCAN) meta-GGA schemes. A Hubbard parameter (U) used to model Coulomb on Ni 3d electrons. The GGA+U shown correctly predict...
Joining of dissimilar metallic materials such as Inconel alloys and steel by vacuum brazing with copper (Cu) filler metal is highly desirable in a wide range applications, for example, construction rotors high-speed electrical motors. However, experiments have shown poor wettability Cu on IN718 during brazing. In this work, molecular dynamics (MD) simulations are performed to study nanoscale interfacial phenomena that occur IN600 using Cu. Hybrid potentials data verified density function...
We present an in-depth discussion of the magnetic ground state α''-Fe16N2 within framework density functional theory (DFT). The exchange-correlation effects are treated using a variety schemes, including local-spin-density approximation, generalized-gradient and Strongly-Constrained-and-Appropriately-Normed (SCAN) scheme. also delineate adding on-site interaction parameter U on Fe sites. Among all schemes considered, only SCAN+U is found to capture surprisingly large magnetization in that...
Bismuth has recently attracted interest in connection with Na-ion battery anodes due to its high volumetric capacity. It reacts Na form 3 Bi which is a prototypical Dirac semimetal nontrivial electronic structure. Density-functional-theory based first-principles calculations are playing key role understanding the fascinating structure of and other topological materials. In particular, strongly-constrained-and-appropriately-normed (SCAN) meta-generalized-gradient-approximation (meta-GGA)...
X-ray Compton scattering experiments along with parallel first-principles computations were carried out on LiNiO2 to understand the effects of W doping this cathode material for Li-ion batteries. By employing high-energy x rays exceeding 100 keV, an insight is gained into fate valence electrons, which are adduced undergo transfer empty O 2p energy bands within active oxide matrix cathode. The substitution Ni shown increase electronic conductivity and enhance total magnetization per atom. Our...
Our Compton profile measurements of Ti and TiH2 using readily available hard X-ray radiation at 27.5 keV, detected by both a Hitachi Vortex silicon-drift detector high-resolution superconducting transition-edge sensor array, are found to be in excellent accord with state-of-the-art density functional theory based calculations. The spherically averaged difference between the profiles is well described an inverted parabola, supporting itinerant behavior electron gas screening protons matrix....
Polyacetylene, a simple polymer, has long been studied for its unique electronic properties, yet the role of correlation in polyacetylene still is not clear. Here, we employ various density functional theory formulations to explore effects on magnetic characteristics by ab initio basis. Our results indicate that subtle beyond generalized gradient approximation lead formation spin-density wave solutions $\pi$-conjugated carbon $p$ orbitals could compete with other solutions, possibly leading...
Evidence is growing that a second dome of high-$T_\mathrm{c}$ superconductivity can be accessed in the cuprates by increasing doping beyond first dome. Here we use \emph{ab initio} methods without invoking any free parameters such as Hubbard $U$, to reveal pressure could turn YBa$_2$Cu$_3$O$_7$ into an ideal candidate for second-dome-superconductivity, displaying predicted signature strongly hybridized $d_{x^2-y^2}$ and $d_{z^2}$ orbitals. Notably, found induce phase transition replacing...
We apply a molecular dynamics scheme to analyze classically chaotic properties of two-dimensional circular billiard system containing two Coulomb-interacting electrons. As such, the resembles prototype model for semiconductor quantum dot. The interaction strength is varied from noninteracting limit with zero potential energy up strongly interacting regime where relative kinetic approaches zero. At weak interactions bouncing maps show jumps between quasi-regular orbits. In strong-interaction...
Abstract Recent discovery of superconductivity in the doped infinite-layer nickelates has renewed interest understanding nature high-temperature more generally. The low-energy electronic structure parent compound NdNiO 2 , role correlations driving superconductivity, and possible relationship betweeen cuprates are still open questions. Here, by comparing LaNiO systematically within a parameter free density functional framework, all-electron first-principles we reveal Nd 4 f- electrons...
Understanding similarities and differences between the cuprate nickelate superconductors is drawing intense current interest. Competing charge orders have been observed recently in $undoped$ infinite-layer nickelates sharp contrast to cuprates which exhibit robust antiferromagnetic insulating ground states. The microscopic mechanisms driving these remain unclear. Here, using in-depth first-principles many-body theory based modeling, we show that parent compound of family, LaNiO$_2$, hosts a...