Award Date
December 2023
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Physics and Astronomy
First Committee Member
Joshua Island
Second Committee Member
David Shelton
Third Committee Member
Yan Zhou
Fourth Committee Member
Keith V. Lawler
Fifth Committee Member
Boo Shan Tseng
Number of Pages
98
Abstract
Josephson junctions have garnered significant attention due to their unique electronic properties and applications in quantum devices. In this thesis, we investigate the fabrication processes and characterization of two-dimensional (2D) Josephson junctions consisting of layered van der Waals materials: niobium diselenide (2H-NbSe2) and few layered tungsten ditelluride (1T’-WTe2). The reduction of dimensionality can bring forth unique characteristics in certain materials that are not seen in their bulk counterparts, making them prime candidates for physical exploration. 2H-NbSe2 is an s-wave superconductor at temperatures near and below 7 K. 1T’-WTe2 is a semimetal in bulk but is an intrinsic quantum spin Hall insulator in monolayer form, with a large (55 meV) band gap. Both materials exhibit exotic behavior, and the coupling of the two provides the necessary environment for entangled quasiparticles known as Majorana zero modes (MZMs). In a topologically protected environment, MZMs could be used to encode quantum information, addressing one of the leading obstacles of decoherence in current solid-state qubits. In our investigation of Josephson junctions with 2H-NbSe2 and few layer 1T’-WTe2, disorder became a prevalent issue, hindering expected electronic transport properties of the Josephson effect. The devices studied in this thesis exhibit transparent and non-transparent Andreev reflections. This comparison sheds light on the distinct behaviors of highly disordered and low-disordered interfaces and their implications for quantum effects.
Keywords
Andreev reflection; Josephson junction; proximity effect; quantum effects; transport; two-dimensional
Disciplines
Condensed Matter Physics | Nanoscience and Nanotechnology
File Format
File Size
2700 KB
Degree Grantor
University of Nevada, Las Vegas
Language
English
Repository Citation
Haley, Kristine Lorraine, "Investigating van der Waals Josephson Junctions with 2H-NbSe2 and 1T’-Wte2" (2023). UNLV Theses, Dissertations, Professional Papers, and Capstones. 4881.
http://dx.doi.org/10.34917/37200507
Rights
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