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Articles 1 - 27 of 27
Full-Text Articles in Physics
Piezoelectricity In Hafnia, Sangita Dutta, Pratyush Buragohain, Sebastjan Glinsek, Claudia Richter, Hugo Aramberri, Haidong Lu, Uwe Schroeder, Emmanuel Defay, Alexei Gruverman, Jorge Íñiguez
Piezoelectricity In Hafnia, Sangita Dutta, Pratyush Buragohain, Sebastjan Glinsek, Claudia Richter, Hugo Aramberri, Haidong Lu, Uwe Schroeder, Emmanuel Defay, Alexei Gruverman, Jorge Íñiguez
Department of Physics and Astronomy: Faculty Publications
Because of its compatibility with semiconductor-based technologies, hafnia (HfO2) is today’s most promising ferroelectric material for applications in electronics. Yet, knowledge on the ferroic and electromechanical response properties of this all-important compound is still lacking. Interestingly, HfO2 has recently been predicted to display a negative longitudinal piezoelectric effect, which sets it apart from classic ferroelectrics (e.g., perovskite oxides like PbTiO3) and is reminiscent of the behavior of some organic compounds. The present work corroborates this behavior, by first-principles calculations and an experimental investigation of HfO2 thin films using piezoresponse force microscopy. Further, the simulations …
Evidence For Surface Effects On The Intermolecular Interactions In Fe (Ii) Spin Crossover Coordination Polymers, Thilini K. Ekanayaka, Hannah Kurz, Kayleigh A. Mcelveen, Guanhua Hao, Esha Mishra, Alpha T. N’Diaye, Rebecca Lai, Birgit Weber, Peter A. Dowben
Evidence For Surface Effects On The Intermolecular Interactions In Fe (Ii) Spin Crossover Coordination Polymers, Thilini K. Ekanayaka, Hannah Kurz, Kayleigh A. Mcelveen, Guanhua Hao, Esha Mishra, Alpha T. N’Diaye, Rebecca Lai, Birgit Weber, Peter A. Dowben
Department of Physics and Astronomy: Faculty Publications
From X-ray absorption spectroscopy (XAS) and X-ray photoemission spectroscopy (XPS) it is evident that the spin state transition behavior of Fe(II) spin crossover coordination polymer crystallites at the surface differs from the bulk. A comparison of four different coordination polymers reveals that the observed surface properties may differ from bulk for a variety of reasons. There are Fe(II) spin crossover coordination polymers with either almost complete switching of the spin state at the surface or no switching at all. Oxidation, differences in surface packing, and changes in coordination could all contribute to making the surface very different from the bulk. …
Comment On “Intensity Interference In A Coherent Spin-Polarized Electron Beam”, Herman Batelaan, Sam Keramati, T. J. Gay
Comment On “Intensity Interference In A Coherent Spin-Polarized Electron Beam”, Herman Batelaan, Sam Keramati, T. J. Gay
Department of Physics and Astronomy: Faculty Publications
No abstract provided.
Primordial Black Holes From A Cosmic Phase Transition: The Collapse Of Fermi-Balls, Kiyoharu Kawana, Ke-Pan Xie
Primordial Black Holes From A Cosmic Phase Transition: The Collapse Of Fermi-Balls, Kiyoharu Kawana, Ke-Pan Xie
Department of Physics and Astronomy: Faculty Publications
We propose a novel primordial black hole (PBH) formation mechanism based on a first-order phase transition (FOPT). If a fermion species gains a huge mass in the true vacuum, the corresponding particles get trapped in the false vacuum as they do not have sufficient energy to penetrate the bubble wall. After the FOPT, the fermions are compressed into the false vacuum remnants to form non-topological solitons called Fermi-balls, and then collapse to PBHs due to the Yukawa attractive force. We derive the PBH mass and abundance, showing that for a [](GeV)FOPT the PBHs could be ∼1017 g and explain …
Experimental Observation Of Polarization-Resolved Nonlinear Thomson Scattering Of Elliptically Polarized Light, Colton Fruhling, Junzhi Wang, Donald Umstadter, Christoph Schulzke, Mahonri Romero, Michael Ware, Justin Peatross
Experimental Observation Of Polarization-Resolved Nonlinear Thomson Scattering Of Elliptically Polarized Light, Colton Fruhling, Junzhi Wang, Donald Umstadter, Christoph Schulzke, Mahonri Romero, Michael Ware, Justin Peatross
Department of Physics and Astronomy: Faculty Publications
We report experimental results from a study of nonlinear Thomson scattering of elliptically polarized light. Polarization-resolved radiation patterns of the scattered light are measured as a function of the elliptical polarization state of the incident laser light. The relativistic electron trajectory in intense elliptically polarized fields leads to the formation of unique radiated polarization states, which are observed by our measurements and predicted by a theoretical model. The polarization of Thomson scattered light depends strongly on the intensity of the incident light due to nonlinearity. The results are relevant to high-field electrodynamics and to research and development of light sources …
Non-Poissonian Ultrashort Nanoscale Electron Pulses, Sam Keramati, Will Brunner, T. J. Gay, Herman Batelaan
Non-Poissonian Ultrashort Nanoscale Electron Pulses, Sam Keramati, Will Brunner, T. J. Gay, Herman Batelaan
Department of Physics and Astronomy: Faculty Publications
The statistical character of electron beams used in current technologies, as described by a stream of particles, is random in nature. Using coincidence measurements of femtosecond pulsed electron pairs, we report the observation of sub-Poissonian electron statistics that are nonrandom due to two-electron Coulomb interactions, and that exhibit an antibunching signal of 1 part in 4. This advancement is a fundamental step toward observing a strongly quantum degenerate electron beam needed for many applications, and in particular electron correlation spectroscopy.
Spin-Orbit Dependence Of Anisotropic Current-Induced Spin Polarization, L. L. Tao, Evgeny Y. Tsymbal
Spin-Orbit Dependence Of Anisotropic Current-Induced Spin Polarization, L. L. Tao, Evgeny Y. Tsymbal
Department of Physics and Astronomy: Faculty Publications
Studies of the current-induced spin polarization (CISP) have been recently reinvigorated due to the discoveries of CISP in some burgeoning materials such as oxide interfaces, van der Waals, and topological quantum materials. Here, we investigate the CISP in two-dimensional systems for different types of spin-orbit coupling (SOC) using the Boltzmann transport theory. We find an anisotropic response of CISP to the current direction which strongly depends on the type of SOC. We demonstrate that the CISP is nonlinear with respect to the SOC magnitude, depends on the Fermi energy, and exhibits two different transport regimes for low or high carrier …
High Sensitivity Multi-Axes Rotation Sensing Using Large Momentum Transfer Point Source Atom Interferometry, Jinyang Li, Gregório R. M. Da Silva, Wayne Cheng-Wei Huang, Mohamed Fouda, Jason Bonacum, Timothy L. Kovachy, Selim M. Shahriar
High Sensitivity Multi-Axes Rotation Sensing Using Large Momentum Transfer Point Source Atom Interferometry, Jinyang Li, Gregório R. M. Da Silva, Wayne Cheng-Wei Huang, Mohamed Fouda, Jason Bonacum, Timothy L. Kovachy, Selim M. Shahriar
Department of Physics and Astronomy: Faculty Publications
A point source interferometer (PSI) is a device where atoms are split and recombined by applying a temporal sequence of Raman pulses during the expansion of a cloud of cold atoms behaving approximately as a point source. The PSI can work as a sensitive multi-axes gyroscope that can automatically filter out the signal from accelerations. The phase shift arising from the rotations is proportional to the momentum transferred to each atom from the Raman pulses. Therefore, by increasing the momentum transfer, it should be possible to enhance the sensitivity of the PSI. Here, we investigate the degree of enhancement in …
Resonant Band Engineering Of Ferroelectric Tunnel Junctions, Jing Su, Xingwen Zheng, Zheng Wen, Tao Li, Shijie Xie, Karin M. Rabe, Xiaohui Liu, Evgeny Y. Tsymbal
Resonant Band Engineering Of Ferroelectric Tunnel Junctions, Jing Su, Xingwen Zheng, Zheng Wen, Tao Li, Shijie Xie, Karin M. Rabe, Xiaohui Liu, Evgeny Y. Tsymbal
Department of Physics and Astronomy: Faculty Publications
We propose energy band engineering to enhance tunneling electroresistance (TER) in ferroelectric tunnel junctions (FTJs). We predict that an ultrathin dielectric layer with a smaller band gap, embedded into a ferroelectric barrier layer, acts as a switch controlling high- and low-conductance states of an FTJ depending on polarization orientation. Using first-principles modeling based on density functional theory, we investigate this phenomenon for a prototypical SrRuO3/BaTiO3/SrRuO3 FTJ with a BaSnO3 monolayer embedded in the BaTiO3 barrier. We show that in such a composite-barrier FTJ, ferroelectric polarization of BaTiO3 shifts the conduction-band minimum of …
Atomic Photoionization By Multiple Temporal Pairs Of Slits, Jean Marcel Ngoko Djiokap
Atomic Photoionization By Multiple Temporal Pairs Of Slits, Jean Marcel Ngoko Djiokap
Department of Physics and Astronomy: Faculty Publications
We study interactions between multiple temporal pairs of slits in coherent control of photoionization of S-state atoms using a pulse train of N + 1 pairs evenly delayed in time by τ , in which the two pulses in a pair with a delay τ0 are counter-rotating circularly polarized. For interacting two double-slit experiments, while Ramsey interference between two identical Archimedean spirals yields pairs of principal spirals, interference of two spirals with opposite handedness does not lead to spirals, but instead to crocodile-eye-like patterns with nictares. For more than two interacting experiments, the resulting patterns turn out just to …
Effect Of Correlated Oxide Electrodes On Disorder Pinning And Thermal Roughening Of Ferroelectric Domain Walls In Epitaxial Pbzr0.2Ti0.8O3 Thin Films, Kun Wang, Yifei Hao, Le Zhang, Yuanyuan Zhang, Xuegang Chen, Xia Hong
Effect Of Correlated Oxide Electrodes On Disorder Pinning And Thermal Roughening Of Ferroelectric Domain Walls In Epitaxial Pbzr0.2Ti0.8O3 Thin Films, Kun Wang, Yifei Hao, Le Zhang, Yuanyuan Zhang, Xuegang Chen, Xia Hong
Department of Physics and Astronomy: Faculty Publications
We report the competing effects of disorder pinning and thermal roughening on ferroelectric domain walls as a function of temperature in epitaxial PbZr0.2Ti0.8O3 thin films deposited on (001) SrTiO3 substrates buffered by three types of correlated oxide electrodes, La0.67Sr0.33MnO3, LaNiO3, and SrIrO3. Piezoresponse force microscopy studies show that the 50-nm PbZr0.2Ti0.8O3 films are uniformly polarized in the as-grown states, with the patterned domain structures persisting above 700 °C. For all three types of films, the domain wall roughness is …
Friedel Oscillations In Graphene Gapped By Breaking Ƥ And T Symmetries: Topological And Geometrical Signatures Of Electronic Structure, Jin Yang, Ding-Fu Shao, Shu-Hui Zhang, Wen Yang
Friedel Oscillations In Graphene Gapped By Breaking Ƥ And T Symmetries: Topological And Geometrical Signatures Of Electronic Structure, Jin Yang, Ding-Fu Shao, Shu-Hui Zhang, Wen Yang
Department of Physics and Astronomy: Faculty Publications
The measurement of Friedel oscillations (FOs) is conventionally used to recover the energy dispersion of electronic structure. Besides the energy dispersion, the modern electronic structure also embodies other key ingredients such as the geometrical and topological properties; it is one promising direction to explore the potential of FOs for the relevant measurement. Here, we present a comprehensive study of FOs in substrate-supported graphene under off-resonant circularly polarized light, in which a valley-contrasting feature and topological phase transition occur due to the combined breaking of inversion (Ƥ) and time reversal (T) symmetries. Depending on the position of …
Kapitza-Dirac Blockade: A Universal Tool For The Deterministic Preparation Of Non-Gaussian Oscillator States, Wayne Cheng-Wei Huang, Herman Batelaan, Markus Arndt
Kapitza-Dirac Blockade: A Universal Tool For The Deterministic Preparation Of Non-Gaussian Oscillator States, Wayne Cheng-Wei Huang, Herman Batelaan, Markus Arndt
Department of Physics and Astronomy: Faculty Publications
Harmonic oscillators count among the most fundamental quantum systems with important applications in molecular physics, nanoparticle trapping, and quantum information processing. Their equidistant energy level spacing is often a desired feature, but at the same time a challenge if the goal is to deterministically populate specific eigenstates. Here, we show how interference in the transition amplitudes in a bichromatic laser field can suppress the sequential climbing of harmonic oscillator states (Kapitza-Dirac blockade) and achieve selective excitation of energy eigenstates, cat states, and other non-Gaussian states. This technique can transform the harmonic oscillator into a coherent two-level system or be used …
Kapitza-Dirac Blockade: A Universal Tool For The Deterministic Preparation Of Non-Gaussian Oscillator States, Wayne Cheng-Wei Huang, Herman Batelaan, Markus Arndt
Kapitza-Dirac Blockade: A Universal Tool For The Deterministic Preparation Of Non-Gaussian Oscillator States, Wayne Cheng-Wei Huang, Herman Batelaan, Markus Arndt
Department of Physics and Astronomy: Faculty Publications
Harmonic oscillators count among the most fundamental quantum systems with important applications in molecular physics, nanoparticle trapping, and quantum information processing. Their equidistant energy level spacing is often a desired feature, but at the same time a challenge if the goal is to deterministically populate specific eigenstates. Here, we show how interference in the transition amplitudes in a bichromatic laser field can suppress the sequential climbing of harmonic oscillator states (Kapitza-Dirac blockade) and achieve selective excitation of energy eigenstates, cat states, and other non-Gaussian states. This technique can transform the harmonic oscillator into a coherent two-level system or be used …
Study Of Quasimonoenergetic Electron Bunch Generation In Self-Modulated Laser Wakefield Acceleration Using Tw Or Sub-Tw Ultrashort Laser Pulses, E. P. Maldonado, R. E. Samad, A. Bonatto, R. P. Nunes, S. Banerjee, N. D. Vieira
Study Of Quasimonoenergetic Electron Bunch Generation In Self-Modulated Laser Wakefield Acceleration Using Tw Or Sub-Tw Ultrashort Laser Pulses, E. P. Maldonado, R. E. Samad, A. Bonatto, R. P. Nunes, S. Banerjee, N. D. Vieira
Department of Physics and Astronomy: Faculty Publications
This work presents a study on laser wakefield electron acceleration in the self-modulated regime (SM-LWFA) using 50-fs laser pulses with energy on the mJ scale, at λ = 0.8 μm, impinging on a thin H2 gas jet. Particle-in-cell simulations were performed using laser peak powers ranging from sub-terawatt to a few terawatts and plasma densities varying from the relativistic self-focusing threshold up to values close to the critical density. The differences in the obtained acceleration processes are discussed. Results show that bunched electron beams with full charge on the nC scale and kinetic energy in the MeV range …
Semiclassical Theory Of Laser-Assisted Dissociative Recombination, Ilya I. Fabrikant, H. B. Ambalampitiya, I. F. Schneider
Semiclassical Theory Of Laser-Assisted Dissociative Recombination, Ilya I. Fabrikant, H. B. Ambalampitiya, I. F. Schneider
Department of Physics and Astronomy: Faculty Publications
We study the process of laser-assisted dissociative recombination of an electron with a molecular cation using a semiclassical approach. In the region outside a reaction sphere the electron motion in the combined laser and Coulomb fields is treated classically. Within the sphere the laser-field effects are neglected, and the recombination probability is obtained from quantum-mechanical cross sections calculated for the laser-free process. Specific calculations are performed for dissociative recombination of H2+ in the field of the intensity 2.09 GW/cm2 and the wavelength 22.8 μm. In the energy region above 1 meV the cross section is significantly …
Spirals And Skyrmions In Antiferromagnetic Triangular Lattices, Wuzhang Fang, Aldo Raeliarijaona, Po-Hao Chang, Alexey Kovalev, Kirill Belashchenko
Spirals And Skyrmions In Antiferromagnetic Triangular Lattices, Wuzhang Fang, Aldo Raeliarijaona, Po-Hao Chang, Alexey Kovalev, Kirill Belashchenko
Department of Physics and Astronomy: Faculty Publications
We study realizations of spirals and skyrmions in two-dimensional antiferromagnets with a triangular lattice on an inversion-symmetry-breaking substrate. As a possible material realization, we investigate the adsorption of transition-metal atoms (Cr, Mn, Fe, or Co) on a monolayer of MoS2, WS2, or WSe2 and obtain the exchange, anisotropy, and Dzyaloshinskii-Moriya interaction parameters using first-principles calculations. Using energy minimization and parallel-tempering Monte Carlo simulations, we determine the magnetic phase diagrams for a wide range of interaction parameters. We find that skyrmion lattices can appear even with weak Dzyaloshinskii-Moriya interactions, but their stability is hindered by magnetic anisotropy. However, a weak easy …
Robust Wavefront Dislocations Of Friedel Oscillations In Gapped Graphene, Shu-Hui Zhang, Jin Yang, Ding-Fu Shao, Zhenhua Wu, Wen Yang
Robust Wavefront Dislocations Of Friedel Oscillations In Gapped Graphene, Shu-Hui Zhang, Jin Yang, Ding-Fu Shao, Zhenhua Wu, Wen Yang
Department of Physics and Astronomy: Faculty Publications
Friedel oscillation is a well-known wave phenomenon which represents the oscillatory response of electron waves to imperfection. By utilizing the pseudospin-momentum locking in gapless graphene, two recent experiments demonstrate the measurement of the topological Berry phase by corresponding to the unique number of wavefront dislocations in Friedel oscillations. Here, we study the Friedel oscillations in gapped graphene, in which the pseudospin-momentum locking is broken. Unusually, the wavefront dislocations do occur like that in gapless graphene, which requires immediate verification in the current experimental condition. The number of wavefront dislocations is ascribed to the invariant pseudospin winding number in gapped and …
Spin Superfluidity In Noncollinear Antiferromagnets, Bo Li, Alexey Kovalev
Spin Superfluidity In Noncollinear Antiferromagnets, Bo Li, Alexey Kovalev
Department of Physics and Astronomy: Faculty Publications
We explore the spin superfluid transport in exchange interaction dominated three-sublattice antiferromagnets. The system in the long-wavelength regime is described by an $SO(3)$ invariant field theory. Additional corrections from Dzyaloshinskii-Moriya interactions or anisotropies can break the symmetry; however, the system still approximately holds a $U(1)$-rotation symmetry. Thus, the power-law spatial decay signature of spin superfluidity is identified in a nonlocal-measurement setup where the spin injection is described by the generalized spin-mixing conductance. We suggest iron jarosites as promising material candidates for realizing our proposal.
Electron Interference In Atomic Ionization By Two Crossing Polarized Ultrashort Pulses, Jean Marcel Ngoko Djiokap, A. V. Meremianin, N. L. Manakov
Electron Interference In Atomic Ionization By Two Crossing Polarized Ultrashort Pulses, Jean Marcel Ngoko Djiokap, A. V. Meremianin, N. L. Manakov
Department of Physics and Astronomy: Faculty Publications
Formation of geometrically regular interference patterns in the photoelectron momentum distributions (PMDs) corresponding to the photoionization of atoms by two single-color, crossing ultrashort pulses is investigated both analytically and numerically. It is shown that, in contrast to the photoionization by monochromatic pulses, PMDs for the ionization by crossing and co-propagating broadband pulses are essentially different (unless both pulses are linearly polarized), namely, when one pulse is linearly polarized along the propagation direction, [], of the circularly polarized (CP) pulse, then interference maxima (minima) of the ionization probability have the form of three-dimensional single-arm regular spirals which are wound along []. …
Two-Dimensional Antiferroelectric Tunnel Junction, Jun Ding, Ding-Fu Shao, Ming Li, Li-Wei Wen, Evgeny Y. Tsymbal
Two-Dimensional Antiferroelectric Tunnel Junction, Jun Ding, Ding-Fu Shao, Ming Li, Li-Wei Wen, Evgeny Y. Tsymbal
Department of Physics and Astronomy: Faculty Publications
Ferroelectric tunnel junctions (FTJs), which consist of two metal electrodes separated by a thin ferroelectric barrier, have recently aroused significant interest for technological applications as nanoscale resistive switching devices. So far, most existing FTJs have been based on perovskite-oxide barrier layers. The recent discovery of the two-dimensional (2D) van der Waals ferroelectric materials opens a new route to realize tunnel junctions with new functionalities and nm-scale dimensions. Because of the weak coupling between the atomic layers in these materials, the relative dipole alignment between them can be controlled by applied voltage. This allows transitions between ferroelectric and antiferroelectric orderings, resulting …
Magnetic And Electron Transport Properties Of Co2Si Nanomagnets, Balamurugan Balasubramanian, Tom A. George, Priyanka Manchanda, Rabindra Pahari, Ahsan Ullah, Ralph Skomski, David J. Sellmyer
Magnetic And Electron Transport Properties Of Co2Si Nanomagnets, Balamurugan Balasubramanian, Tom A. George, Priyanka Manchanda, Rabindra Pahari, Ahsan Ullah, Ralph Skomski, David J. Sellmyer
Department of Physics and Astronomy: Faculty Publications
Magnetotransport and ferromagnetism in thin films of Co2Si nanoclusters are investigated experimentally and theoretically. The nanoclusters are fabricated by an inert-gas condensation-type cluster-deposition method and have an average size of 11.3 nm. Unlike the bulk Co2Si that exhibits a very weak net magnetic moment only below 10 K, the nanoclusters exhibit room-temperature ferromagnetism with a substantial saturation magnetization. Key features of the system are its closeness to the Stoner transition, magnetic moments induced by spin polarization starting from surface atoms, and nonuniaxial anisotropy associated with the orthorhombic crystal structure of Co2Si. A method is …
Ferromagnetic Liquid Droplets With Adjustable Magnetic Properties, Xuefei Wu, Robert Streubel, Xubo Liu, Paul Y. Kim, Yu Chai, Qin Hu, Dong Wang, Peter Fischer, Thomas P. Russell
Ferromagnetic Liquid Droplets With Adjustable Magnetic Properties, Xuefei Wu, Robert Streubel, Xubo Liu, Paul Y. Kim, Yu Chai, Qin Hu, Dong Wang, Peter Fischer, Thomas P. Russell
Department of Physics and Astronomy: Faculty Publications
The assembly and jamming of magnetic nanoparticles (NPs) at liquid–liquid interfaces is a versatile platform to endow structured liquid droplets with a magnetization, i.e., producing ferromagnetic liquid droplets (FMLDs). Here, we use hydrodynamics experiments to probe how the magnetization of FMLDs and their response to external stimuli can be tuned by chemical, structural, and magnetic means. The remanent magnetization stems from magnetic NPs jammed at the liquid–liquid interface and dispersed NPs magneto-statically coupled to the interface. FMLDs form even at low concentrations of magnetic NPs when mixing nonmagnetic and magnetic NPs, since the underlying magnetic dipole-driven clustering of magnetic NP-surfactants …
Surface Acoustic Waves Increase Magnetic Domain Wall Velocity, Anil Adhikari, S. Adenwalla
Surface Acoustic Waves Increase Magnetic Domain Wall Velocity, Anil Adhikari, S. Adenwalla
Department of Physics and Astronomy: Faculty Publications
Domain walls in magnetic thin films are being explored for memory applications and the speed at which they move has acquired increasing importance. Magnetic fields and currents have been shown to drive domain walls with speeds exceeding 500 m/s. We investigate another approach to increase domain wall velocities, using high frequency surface acoustic waves to create standing strain waves in a 3 micron wide strip of magnetic film with perpendicular anisotropy. Our measurements, at a resonant frequency of 248.8 MHz, indicate that domain wall velocities increase substantially, even at relatively low applied voltages. Our findings suggest that the strain wave …
Integrating Out New Fermions At One Loop, Andrei Angelescu, Peisi Huang
Integrating Out New Fermions At One Loop, Andrei Angelescu, Peisi Huang
Department of Physics and Astronomy: Faculty Publications
We present the fermionic universal one-loop effective action obtained by integrating out heavy vector-like fermions at one loop using functional techniques. Even though previous approaches are able to handle integrating out heavy fermions with non-chiral interactions, i.e. vanishing γ5 interaction terms, the computations proceed in a tedious manner that obscures a physical interpretation. We show how directly tackling the fermionic functional determinant not only allows for a much simpler and transparent computation, but is also able to account for chiral interaction terms in a simple, algorithmic way. Finally, we apply the obtained results to integrate out at one loop …
Methanol Carbonylation To Acetaldehyde On Au Particles Supported By Single-Layer Mos2 Grown On Silica, Kortney Almeida, Katerina Chagoya, Alan Felix, Tao Jiang, Duy Le, Takat B. Rawal, Prescott E. Evans, Michelle Wurch, Koichi Yamaguchi, Peter A. Dowben, Ludwig Bartels, Talat S. Rahman, Richard G. Blair
Methanol Carbonylation To Acetaldehyde On Au Particles Supported By Single-Layer Mos2 Grown On Silica, Kortney Almeida, Katerina Chagoya, Alan Felix, Tao Jiang, Duy Le, Takat B. Rawal, Prescott E. Evans, Michelle Wurch, Koichi Yamaguchi, Peter A. Dowben, Ludwig Bartels, Talat S. Rahman, Richard G. Blair
Department of Physics and Astronomy: Faculty Publications
Homogenous single-layer MoS2 films coated with sub-single layer amounts of gold are found to isolate the reaction of methanol with carbon monoxide, the fundamental step toward higher alcohols, from an array of possible surface reactions. Active surfaces were prepared from homogenous single-layer MoS2 films coated with sub-single layer amounts of gold. These gold atoms formed clusters on the MoS2 surface. A gas mixture of carbon monoxide (CO) and methanol (CH3OH) was partially converted to acetaldehyde (CH3CHO) under mild process conditions (308 kPa and 393 K). This carbonylation of methanol to a C2 species …
Regular And In-Plane Skyrmions And Antiskyrmions From Boundary Instabilities, Shane Sandhoefner, Aldo Raeliarijaona, Rabindra Nepal, Dalton Snyder-Tinoco, Alexey Kovalev
Regular And In-Plane Skyrmions And Antiskyrmions From Boundary Instabilities, Shane Sandhoefner, Aldo Raeliarijaona, Rabindra Nepal, Dalton Snyder-Tinoco, Alexey Kovalev
Department of Physics and Astronomy: Faculty Publications
We formulate a theory of skyrmion and antiskyrmion generation using magnetic field and charge current pulses. We show that the topological defect can be created at an edge of a system with Dzyaloshinskii-Moriya interaction (DMI) as well as at a boundary between regions with different DMI. We consider both perpendicular and in-plane (also known as magnetic bimerons) versions of skyrmions and antiskyrmions. We show that the magnetization twist in the vicinity of an edge or a boundary is described by a kink solution, the presence of which can instigate the generation of topological defects. We study the collective excitations of …