<p>Scientific progress often relies on unexpected discoveries and unique observations. In</p>
<p>fact, many of the most groundbreaking scientific advances throughout history have been the</p>
<p>result of serendipitous events. For instance, the discovery of penicillin by Alexander Fleming</p>
<p>was a result of him noticing a mold growing on a petri dish that was contaminating his</p>
<p>bacterial culture. Similarly, the discovery of the cosmic microwave background radiation,</p>
<p>which is considered one of the strongest pieces of evidence for the Big Bang theory, was</p>
<p>the result of two scientists accidentally stumbling upon it while conducting a completely</p>
<p>different experiment. These types of unexpected discoveries can lead to new avenues of</p>
<p>research and open up entirely new fields of study. During my PhD, I experienced a similar</p>
<p>phenomenon when I stumbled upon an anomaly in my experimental data that led me down a</p>
<p>completely new path of investigation. This unexpected discovery not only provided me with</p>
<p>new insights into the underlying mechanisms of my research, but also opened new avenues for</p>
<p>future research directions. It was a reminder that sometimes the greatest scientific progress</p>
<p>can come from the most unexpected places.</p>
<p>My primary focus was initially directed towards topological superconductivity. However,</p>
<p>this research direction was modified by unexpected findings while characterizing a SQUID.</p>
<p>Specifically, a unique response by a Josephson junction was observed when exposed to an inplane</p>
<p>magnetic field. Chapter 1 details our experimental results on the SQUID. We observed</p>
<p>intriguing effects resulting from the in-plane magnetic field in the asymmetric evolution of</p>
<p>the Fraunhofer pattern suggesting the existence of additional underlying physics in the heterostructure,</p>
<p>which may have been previously overlooked. This serendipitous finding served</p>
<p>as the impetus to explore simpler superconducting devices such as nanowires and rings.</p>
<p>Remarkably, subsequent investigations into the critical current of a superconducting ring revealed</p>
<p>a bi-modal histogram arising from the application of an in-plane magnetic field, which</p>
<p>was an unforeseen outcome. This adds to our observations made in chapter 1. Chapter 2 details</p>
<p>the unique properties of Al-InAs superconducting rings. Further experiments involving</p>
<p>a superconducting nanowire resulted in the observation of non-reciprocal critical current under</p>
<p>an in-plane magnetic field perpendicular to the current direction, subsequently referred to as the superconducting diode effect. Chapter 3 delves into the non-reciprocal properties</p>
<p>of an Al-InAs superconducting nanowire. Our findings revealed the diamagnetic source of</p>
<p>non-reciprocity generic to multi-layer superconductors. Finally, chapter 4 provides a detailed</p>
<p>account of the fabrication processes for the superconducting devices, along with a discussion</p>
<p>of the measurement techniques employed to unveil the underlying physics.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/23681796 |
| Date | 14 July 2023 |
| Creators | Ananthesh Sundaresh (16543269) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/SEARCH_FOR_TOPOLOGICAL_SUPERCONDUCTIVITY_IN_SUPERCONDUCTOR-SEMICONDUCTOR_HETEROSTRUCTURES/23681796 |
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