Publications
Valley- and spin-polarized Landau levels in monolayer WSe2
Electrons in monolayer transition metal dichalcogenides are characterized by valley and spin quantum degrees of freedom, making it possible to explore new physical phenomena and to foresee novel applications in the fields of electronics and optoelectronics. Theoretical proposals further suggest that Berry curvature effects, together with strong spin-orbit interactions, can generate unconventional Landau levels (LLs) under a perpendicular magnetic field. In particular, these would support valley- and spin-polarized chiral edge states in the quantum Hall regime.
Topological electromagnetic responses of bosonic quantum Hall, topological insulator, and chiral semimetal phases in all dimensions
We calculate the topological part of the electromagnetic response of bosonic integer quantum Hall (BIQH) phases in odd (space-time) dimensions, and bosonic topological insulator (BTI) and bosonic chiral semimetal (BCSM) phases in even dimensions. To do this, we use the nonlinear sigma model (NLSM) description of bosonic symmetry-protected topological (SPT) phases, and the method of gauged Wess-Zumino (WZ) actions.
Upconversion-Triggered Charge Separation in Polymer Semiconductors
Upconversion is a unique optical property that is driven by a sequential photon pumping and generation of higher energy photons in a consecutive manner. The efficiency improvement in photovoltaic devices can be achieved when upconverters are integrated since upconverters contribute to the generation of extra photons. Despite numerous experimental studies confirming the relationship, fundamental explanations for a real contribution of upconversion to photovoltaic efficiency are still in demand.
REPLY to JANOSCHEK et AL.: The excited δ-phase of plutonium
Putting the squeeze on superconductivity: The exotic superconductor Sr2RuO4 yields new secrets under large uniaxial pressures
A KIM-compliant potfit for fitting sloppy interatomic potentials: Application to the EDIP model for silicon
Fitted interatomic potentials are widely used in atomistic simulations thanks to their ability to compute the energy and forces on atoms quickly. However, the simulation results crucially depend on the quality of the potential being used. Force matching is a method aimed at constructing reliable and transferable interatomic potentials by matching the forces computed by the potential as closely as possible, with those obtained from first principles calculations.
Towards a generalized iso-density continuum model for molecular solvents in plane-wave DFT
Implicit electron-density solvation models offer a computationally efficient solution to the problem of calculating thermodynamic quantities of solvated systems from first-principles quantum mechanics. However, despite much recent interest in such models, to date the applicability of such models in the plane-wave context to non-aqueous solvents has been limited because the determination of the model parameters requires fitting to a large database of experimental solvation energies for each new solvent considered.
Highly flexible and semi-transparent Ag-Cu alloy electrodes for high performance flexible thin film heaters
We investigated the properties of thermally evaporated Ag-Cu films for application as flexible and semi-transparent electrodes for semi-transparent flexible thin film heaters (TFHs) and heat shielding films (HSFs). The effects of Ag-Cu thickness on the electrical, optical, morphological, and mechanical properties of the Ag-Cu films were investigated in detail. Based on figure of merit values calculated from the sheet resistance and optical transmittance, we optimized the thickness of the Ag-Cu alloy film.
JDFTx: Software for joint density-functional theory
Density-functional theory (DFT) has revolutionized computational prediction of atomic-scale properties from first principles in physics, chemistry and materials science. Continuing development of new methods is necessary for accurate predictions of new classes of materials and properties, and for connecting to nano- and mesoscale properties using coarse-grained theories. JDFTx is a fully-featured open-source electronic DFT software designed specifically to facilitate rapid development of new theories, models and algorithms.
Long-Term High-Resolution Imaging of Developing C. elegans Larvae with Microfluidics
Long-term studies of Caenorhabditis elegans larval development traditionally require tedious manual observations because larvae must move to develop, and existing immobilization techniques either perturb development or are unsuited for young larvae. Here, we present a simple microfluidic device to simultaneously follow development of ten C. elegans larvae at high spatiotemporal resolution from hatching to adulthood (∼3 days).