Previous work has highlighted the difficulties students have when explaining wave behavior. We present an investigation of chemistry students’ understanding of the double-slit experiment, where students were asked to explain a series of PhET simulations illustrating a single continuous light source, single-slit diffraction, and double-slit interference. We observed a variation in student reasoning and students were categorized into groups based on their ability to explain and generate a mechanism for the double-slit experiment. Some students struggled to explain the features of waves which impacted their reasoning about interference and caused them to rely on intuition to generate explanations. Other students were able to productively incorporate their previous knowledge about wave behavior, with their observations from the simulations, to build a robust mechanism for wave interference. However, students generally exhibited a limited understanding of interference, and specifically attending to the key features of waves during instruction can promote more sophisticated reasoning about this phenomenon.
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Graphene-based analog of single-slit electron diffraction
In this paper, we report on the experimental demonstration of single-slit diffraction exhibited by electrons propagating in encapsulated graphene with an effective de Broglie wavelength corresponding to their attributes as massless Dirac fermions. Nanometer-scale device designs were implemented to fabricate a single-slit followed by five detector paths. Predictive calculations were also utilized to readily understand the observations reported. These calculations required the modeling of wave propagation in ideal case scenarios of the reported device designs to more accurately describe the observed single-slit phenomenon. This experiment was performed at room temperature and 190 K, where data from the latter highlighted the exaggerated asymmetry between electrons and holes, recently ascribed to slightly different Fermi velocities near the 𝐾 point. This observation and device concept may be used for building diffraction switches with versatile applicability.
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- Award ID(s):
- 2041972
- PAR ID:
- 10514715
- Publisher / Repository:
- Physical Review B
- Date Published:
- Journal Name:
- Physical Review B
- Volume:
- 108
- Issue:
- 12
- ISSN:
- 2469-9950
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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