<p>The macroscopic quantum phenomenology of superconductivity has attracted broad interest from both scientific research and applications. Many exotic physics found in the first high $T_C$ superconductor family cuprate remain unsolved even after 30 years of intense study. Angle-Resolved Photoemission Spectroscopy (ARPES) provides the direct probe to the major information of the electronic interactions, which plays the key role in these exotic physics including high $T_C$ superconductivity. ARPES is also the best tool to study the electronic structure in materials that potentially hold high $T_C$ superconductivity, providing insight for materials research and design.
In this thesis, we present the ARPES study of the cuprate high $T_C$ superconductor Pb doped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$, and potential high $T_C$ superconductors K doped \textit{p}-terphenyl, and trilayer nickelate La$_4$Ni$_3$O$_{10}$. For Pb doped Bi2212, our study focuses on the key part of the electronic interactions---the self-energies. With the development of a novel 2-dimensional analysis technique, we present the first quantitative extraction of the fully causal complex self-energies. The extracted information reveals a conversion of the diffusive strange-metal correlations into a coherent highly renormalized state at low temperature followed by the enhancement of the number of states for pairing. We then further show how this can lead to a strong positive feedback effect that can stabilize and strengthen superconducting pairing. In K doped \textit{p}-terphenyl, we discover low energy spectral gaps that persist up to 120 K, consistent with potential Meissner effect signal from previous studies. Among a few potential origins for these gaps, we argue that the electron pairing scenario is most likely. For La$_4$Ni$_3$O$_{10}$, we present the Fermiology and electron dynamics of this material, and they show certain similarities to the cuprate electronic structure, as well as a few unique features.
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:10642070 |
| Date | 05 January 2018 |
| Creators | Li, Haoxiang |
| Publisher | University of Colorado at Boulder |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
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