Arboleda

Density Functional Theory–Based Study of the Structural Properties of Hexagonal Boron Nitride/Graphene Hetero-Bilayer and Silicene/Hexagonal Boron Nitride/Graphene Hetero-Structures for Thin Film Transistor Applications

Abstract

The geometric properties and structural stability of hexagonal boron nitride on graphene (h-BN/G) hetero-bilayer and silicene on hexagonal boron nitride on graphene (Si/h-BN/G) hetero-structure were investigated using density functional theory. The calculations were performed through the Vienna Ab Initio Simulation package (VASP) implemented with three different approximations, namely, the local density approximation (LDA), general gradient approximation (GGA), and GGA with Tkatchenko–Scheffler van der Waals (vdW) correction. In reference to the experimental interlayer distance and binding energy between graphitic layers, the h-BN/G hetero-bilayer and Si/h-BN/G hetero-structures were stable. Read More

Conceptual Understanding of Forces Among Physics Majors

Conceptual Understanding of Forces Among Physics Majors

Abstract

Conceptual understanding of forces among physics majors at De La Salle University were evaluated using the Force Concept Inventory (FCI). The FCJ scores were found to vary from an average of 23.0% for freshmen to 39.74% for seniors. Only one out of 81 physics majors of all year levels was found to be a clearly Newtonian thinker. While there is a marked difference in the understanding of inertia and falling bodies between freshmen and seniors, conceptual understanding of kinematics, Newton’s 2’d and 3’d Laws, and force identification did not reach the 50% level from first to fourth year. Read More

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Quasilocal Background Approach to the One-loop Effective Action

Abstract

The one-loop effective action that accommodates an arbitrary number of covariant derivatives of a strong but slowly-varying background field is presented in closed form.  The internal symmetry and spacetime dimension are kept arbitrary in the formalism.  The first few terms in the perturbative expansion of the one-loop effective action are derived and are found to agree with those obtained using popular methods. Read More