A ball on a stick is a common and simple activity for teaching the phases of the Moon. This activity, like many others in physics and astronomy, gives students a perspective they otherwise could only imagine. For Moon phases, a third person view and control over time allows students to rapidly build a mental model that connects all the moving parts. Computer simulations of many traditional physics and astronomy activities provide new features, controls, or vantage points to enhance learning beyond a hands-on activity.

The Conceptual Survey of Electricity and Magnetism (CSEM) has been utilized to measure learning gains in electricity and magnetism (E and M) physics courses, where “correct“ vs “incorrect“ responses are typically used for analysis. However, such comparisons do not necessarily identify specific changes in student reasoning from pre- to post-instruction. To address this issue, we have generated network-like graphs for each question: Responses at pre- and post-test are represented by nodes connected by edges representing the change in student response choice.

While laboratory instruction is a cornerstone of physics education, the impact of student behaviours in labs on retention, persistence in the field, and the formation of students' physics identity remains an open question. In this study, we performed in-lab observations of student actions over two semesters in two pedagogically different sections of the same introductory physics course. We used a cluster analysis to identify different categories of student behaviour and analyzed how they correlate with lab structure and gender.

Dimensionality and connectivity among octahedra play important roles in determining the properties, electronic structure, and phase transitions of transition-metal oxides. Here we demonstrate the epitaxial growth of (110)-oriented alternating layers of IrO2 and TiO2, both of which have the rutile structure. These (IrO2)n/(TiO2)2 superlattices consist of IrO6 and TiO6 octahedra tiled in a hyperconnected, edge- and corner-sharing network.

We fabricate devices in which a magnetic nanopillar spin valve makes contact to a Co/Pt bilayer thin film with perpendicular magnetic anisotropy, to achieve local control of domains in the Co/Pt bilayer underneath the nanopillar. The goal is to develop the ability to nucleate, detect, and annihilate magnetic skyrmions in the Co/Pt using spin-polarized currents from the nanopillar. We demonstrate the ability to distinguish the local behavior of the Co/Pt film beneath the nanopillar from the extended film and show that the two can switch independently of each other.

We analyze the interplay between a d-wave uniform superconducting and a pair-density-wave (PDW) order parameter in the neighborhood of a vortex. We develop a phenomenological nonlinear sigma model, solve the saddle-point equation for the order-parameter configuration, and compute the resulting local density of states in the vortex halo. The intertwining of the two superconducting orders leads to a charge density modulation with the same periodicity as the PDW, which is twice the period of the charge density wave that arises as a second harmonic of the PDW itself.

In this work we propose a theory for the deconfined quantum critical point (DQCP) for spin-1/2 systems on a triangular lattice, which is a direct unfine-tuned quantum phase transition between the standard "3×3" noncollinear antiferromagnetic order (or the so-called 120 state) and the "12×12" valence solid bond (VBS) order, both of which are very standard ordered phases often observed in numerical simulations.

Electron tunneling into a system with strong interactions is known to exhibit an anomaly, in which the tunneling conductance vanishes continuously at low energy due to many-body interactions. Recent measurements have probed this anomaly in a quantum Hall bilayer of the half-filled Landau level, and shown that the anomaly apparently gets stronger as the half-filled Landau level is increasingly spin polarized.

We demonstrate robust optical bistability, the phenomenon of two well-discriminated stable states depending upon the history of the optical input, in fully suspended monolayers of WSe2 at low temperatures near the exciton resonance. Optical bistability has been achieved under continuous-wave optical excitation that is red-detuned from the exciton resonance at an intensity level of 103 W/cm2. The observed bistability is originated from a photothermal mechanism, which provides both optical nonlinearity and passive feedback, two essential elements for optical bistability.

Samarium hexaboride is a classic three-dimensional mixed valence system with a high-Temperature metallic phase that evolves into a paramagnetic charge insulator below 40 K. A number of recent experiments have suggested the possibility that the low-Temperature insulating bulk hosts electrically neutral gapless fermionic excitations.