A5040445832- Magnetism in coordination complexes
- Quantum and electron transport phenomena
- Topological Materials and Phenomena
- Magnetic properties of thin films
- Magnetic and transport properties of perovskites and related materials
- Quantum many-body systems
- Physics of Superconductivity and Magnetism
- Porphyrin and Phthalocyanine Chemistry
- ZnO doping and properties
- Graphene research and applications
- 2D Materials and Applications
- Molecular Junctions and Nanostructures
- Iron-based superconductors research
- Advanced Condensed Matter Physics
- Electron Spin Resonance Studies
- Organic and Molecular Conductors Research
- Rare-earth and actinide compounds
- Advanced Physical and Chemical Molecular Interactions
- Advanced NMR Techniques and Applications
- Quantum Computing Algorithms and Architecture
- Theoretical and Computational Physics
- Phase-change materials and chalcogenides
- Force Microscopy Techniques and Applications
- Nanocluster Synthesis and Applications
- Magnetic Bearings and Levitation Dynamics
Central Michigan University
2024
The University of Texas at El Paso
2023-2024
Linnaeus University
2010-2022
Virginia Commonwealth University
2013-2015
The University of Texas at Arlington
2008-2010
Purdue University West Lafayette
2006-2009
University of Wollongong
1997
The quantum anomalous Hall effect (QAHE) has recently been reported to emerge in magnetically doped topological insulators. Although its general phenomenology is well established, the microscopic origin far from being properly understood and controlled. Here, we report on a detailed systematic investigation of transition metal (TM) ${\mathrm{Sb}}_{2}{\mathrm{Te}}_{3}$. By combining density functional theory calculations with complementary experimental techniques, i.e., scanning tunneling...
We report on a study of the electronic and magnetic properties triangular antiferromagnetic ${{\text{Cu}}_{3}}$ single-molecule magnet, based spin-density-functional theory. Our calculations show that low-energy are correctly described by an effective three-site spin $s=1/2$ Heisenberg model, with exchange coupling $J\ensuremath{\approx}5\text{ }\text{meV}$. The ground-state manifold model is composed two degenerate $S=1/2$ doublets opposite chirality. Due to lack inversion symmetry in...
We have performed electron transport and angle-resolved photo-emission spectroscopy (ARPES) measurements on single crystals of transition metal dipnictide TaAs2cleaved along the (2¯01) surface which has lowest cleavage energy. A Fourier transform Shubnikov-de Haas oscillations shows four different peaks whose angular dependence was studied with respect to angle between magnetic field [2¯01] direction. The results indicate elliptical shape Fermi cross-sections. Additionally, a mobility...
We present first-principles results on the structural, electronic, and magnetic properties of a new family two-dimensional antiferromagnetic (AFM) manganese chalcogenides, namely, monolayer $\mathrm{Mn}X$ Janus $X\mathrm{Mn}Y$ ($X,Y=\mathrm{S}$, Se, Te), among which MnSe was recently synthesized in experiments [Aapro et al., ACS Nano 15, 13794 (2021)]. By carrying out calculations phonon dispersion ab initio molecular dynamics simulations, we first confirmed that these systems, characterized...
Frustrated triangular molecule magnets such as {Cu${}_{3}$} are characterized by two degenerate $S=1/2$ ground states with opposite chirality. Recently, it has been proposed theoretically [M. Trif et al., Phys. Rev. Lett. 101, 217201 (2008)] and verified ab initio calculations F. Islam B 82, 155446 (2010)] that an external electric field can efficiently couple these chiral spin states, even in the absence of spin-orbit interaction (SOI). The SOI is, nevertheless, important since introduces a...
Using first-principles methods, we study theoretically the properties of an individual ${{\text{Fe}}_{4}}$ single-molecule magnet (SMM) attached to metallic leads in a single-electron transistor geometry. We show that conductive do not affect spin ordering and magnetic anisotropy neutral SMM. On other hand, have strong effect on charged states molecule, which are probed Coulomb blockade transport. Furthermore, demonstrate external electric potential, modeling gate electrode, can be used...
Frustrated triangular molecular magnets (MMs) with antiferromagnetic ground states (GSs) are an important class of magnetic systems potential applications in quantum information processing. The twofold degenerate GS these molecules, characterized by spin chirality, can be utilized to encode qubits for computing. Furthermore, because the lack inversion symmetry electric field couples directly opposite allowing a very efficient and fast control qubits. In this paper we present theoretical...
Breaking time-reversal symmetry in three-dimensional topological insulator thin films can lead to different quantum phases, such as the Chern (CI) phase and axion (AI) phase. Using first-principles density functional theory methods, we investigate onset of these two phases a trilayer heterostructure consisting ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ $({\mathrm{Bi}}_{2}{\mathrm{Te}}_{3})$ TI film sandwiched between antiferromagnetic MnTe layers. We find that an orthogonal exchange field from...
We study the hopping transport of a quantum particle through randomly diluted percolation clusters in two dimensions realized both on square and triangular lattices. investigate nature localization by calculating transmission coefficient as function energy ( -2<E<2 units integral tight-binding Hamiltonian) disorder, q (probability that given site lattice is not available to particle). Our based finite-size scaling suggests existence delocalized states depends amount disorder present system....
(Ga,Mn)As having a wurtzite crystal structure was coherently grown by molecular beam epitaxy on the {1100} side facets of (Ga,In)As nanowires and further encapsulated (Ga,Al)As low temperature GaAs. For first time, truly long-range ferromagnetic magnetic order is observed in non-planar (Ga,Mn)As, which attributed to more effective hole confinement shell containing Mn proper selection/choice both core outer materials.
Introducing magnetic impurities into clusters of simple metals can create localized states for higher angular momentum quantum numbers (l = 2 or 3) that breed magnetism analogous to in virtual bound metallic hosts, offering a new recipe superatoms. In this work, we demonstrate MnCa(n) containing 6-15 Ca atoms show spin moment 5.0 μB irrespective the cluster size. Theoretical analysis reveals Mn d hybridize only partially with superatomic and introduce extra majority minority states, largely...
Using first-principles density functional theory calculations, combined with a topological analysis, we have investigated the electronic properties of $Cd_3As_2$ and $Na_3Bi$ Dirac semimetals doped non-magnetic magnetic impurities. Our systematic analysis shows that selective breaking inversion, rotational time-reversal symmetry, controlled by specific choices impurity doping, induces phase transitions from original semimetal to variety phases such as, insulator, trivial semimetal, Weyl...
We present a computational study of individual and pairs substitutional Mn impurities on the (110) surface GaAs samples based density functional theory. focus anisotropy properties these magnetic centers their dependence on-site correlations, spin-orbit interaction, surface-induced symmetry-breaking effects. For impurity surface, associated acceptor-hole wave function tends to be more localized around than for an in bulk GaAs. The energy isolated is order 1 meV, can related orbital moment...
Combining density functional theory calculations and microscopic tight-binding models, we investigate theoretically the electronic magnetic properties of individual substitutional transition-metal impurities (Mn Fe) positioned in vicinity (110) surface GaAs. For case ${[{\mathrm{Mn}}^{2+}]}^{0}$ plus acceptor-hole (h) complex, results a model including explicitly impurity $d$ electrons are good agreement with approaches that treat spin as an effective classical vector. Fe, where both neutral...
Frustrated triangular molecular magnets are a very important class of magnetic molecules since the absence inversion symmetry allows an external electric field to couple directly with spin chirality that characterizes their ground state. The spin-electric coupling in these leads efficient and fast method manipulating states, making them exciting candidate for quantum information processing. efficiency depends on dipole between chiral states molecules. In this paper, we report...
We investigate the properties of a single substitutional Mn impurity and its associated acceptor state on (111) surface ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ topological insulator. Combining ab initio calculations with microscopic tight-binding modeling, we identify effects inversion symmetry time-reversal-symmetry breaking electronic states in vicinity Dirac point. In agreement experiments, find evidence that ion is $+2$ valence introduces an bulk band gap. The has predominantly $p$...
Abstract Atomic hydrogen adsorptions on the (020) surface of α‐Pu and effects relaxation adsorption properties have been studied using a relativistic extension full‐potential augmented plane wave with local orbital basis method. The has modeled by four‐layer periodic slab consisting 32 Pu atoms layer anti‐ferromagnetic arrangement. for four different sites, namely top, hollow, short bridge long sites investigated in detail. All computations carried out at two theoretical levels, scalar level...
Stabilization of magnetic order in clusters/nanoparticles at elevated temperatures is a fundamentally challenging problem. The anisotropy energy (MAE) that prevents the thermal fluctuations magnetization direction can be around 1–10 K free transition metal clusters dozen atoms. Here we demonstrate graphene support lead to an magnitude enhancement supported species. Our studies show MAE Co5 and Co13 on increase by factors 2.6 25, respectively. linked splitting selected electronic orbitals...
We show that the magnetic anisotropy energy (MAE) in cobalt clusters can be significantly enhanced by doping them with group IV elements. Our first-principles electronic structure calculations Co4C2 and Co12C4 have MAEs of 25 K 61 K, respectively. The large MAE is due to controlled mixing between Co d- C p-states further tuned replacing Si. Larger assemblies such primitive units are shown stable exceeding 100 as small 1.2 nm, agreement recent observation coercivity. These results may pave...
The chiral Fe3O(NC5H5)3(O2CC6H5)6 molecular cation, with C3 symmetry, is composed of three six-fold coordinated spin-carrying Fe3+ cations that form a perfect equilateral triangle. Experimental reports demonstrating the spin-electric effect in this system also identify presence magnetic uniaxis and suggest molecule may be good candidate for an externally controllable qubit. Here, we demonstrate, using standard density-functional methods, behavior could even more interesting as there are...
Frustrated triangular molecular magnets (MMs) with anti-ferromagnetic ground states (GS) are an important class of magnetic systems potential applications in quantum information processing. The two-fold degenerate GS these molecules, characterized by spin chirality, can be utilized to encode qubits for computing. Furthermore, because the lack inversion symmetry electric field couples directly opposite allowing a very efficient and fast control qubits. In this work we present theoretical...