Vibrational defects at the boson peak in 2D glasses
The boson peak is a well known anomaly in glasses and amorphous materials which is related to the thermal properties of such materials. However, its origin is still a subject of active research. Recently, a theory based around string-like vibrational defects has been proposed and studied by vario...
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| Format: | Final Year Project |
| Language: | English |
| Published: |
Nanyang Technological University
2024
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| Online Access: | https://hdl.handle.net/10356/181261 |
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| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | The boson peak is a well known anomaly in glasses and amorphous materials which is
related to the thermal properties of such materials. However, its origin is still a subject of active
research. Recently, a theory based around string-like vibrational defects has been proposed and
studied by various research groups. In this study, we will build off of previous works in this
domain. Using computational tools such as molecular dynamics simulations to obtain model
glassy systems, we first conduct a replication study to understand and verify the existence of
these stringlets. Subsequently, we propose an alternate method of obtaining defects at the
boson peak by disentangling quasi-localised modes from phonons at the boson peak. We then
characterise the geometry and sizes of both types of defects, finding a them to be 2D in 2D
glasses. We also attempt to reconcile the two methods of obtaining defects and suggest that
they are both valid ways of identifying defects in amorphous solids. Finally, we relate the
occurrence of these defects back to the boson peak, proposing that these defects regulate the
size of the boson peak. |
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