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Electron-lattice Interactions in Functional Materials Studied by Ultrafast Electron Diffraction
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Electron-lattice Interactions in Functional Materials Studied by Ultrafast Electron Diffraction. |
| 개인저자 | Konstantinova, Tatiana. |
| 단체저자명 | State University of New York at Stony Brook. Physics. |
| 발행사항 | [S.l.]: State University of New York at Stony Brook., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 130 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-05B. Dissertation Abstract International |
| ISBN | 9781687983572 |
| 학위논문주기 | Thesis (Ph.D.)--State University of New York at Stony Brook, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-05, Section: B.
Advisor: Zhu, Yimei. |
| 이용제한사항 | This item must not be sold to any third party vendors.This item must not be added to any third party search indexes. |
| 요약 | Ultrafast Electron Diffraction (UED) provides a unique tool for separating the role of the crystal lattice in many-body interactions in complex materials. This technique utilizes short pulses of high-energy electrons to get time-series of diffraction patterns that reveal nonequilibrium structural evolution in a photoexcited sample. Through analysis of changes in the diffraction patterns, a full picture of atomic rearrangement can be reconstructed. The characteristic time scales of the lattice dynamics provide a clue to the processes that govern them.In this work, UED is applied to study diverse interactions between lattice and electronic degrees of freedom in superconducting Bi-2212 and FeSe single crystals. On the example of Bi-2212 we have revealed how energy, absorbed by electrons from a laser pulse, is transferred to and redistributed between various atomic vibrations in case of preferential electron-phonon coupling, which is common for a number of functional quantum materials, such as graphene and charge density wave compounds.Observation of nonequilibrium lattice dynamics in FeSe crystals with UED revealed lattice distortions that locally break the lattice symmetry, a feature that gets lost when probed at equilibrium with large-scale tools, such as Rietveld refinement. We have demonstrated that the distortions couple to electronic degrees of freedom (nematic fluctuations) and are involved in the formation of the nematic phase, deemed precursor of superconductivity in Fe-based compounds. This thesis shows how useful information about lattice dynamics can be extracted by analyzing every aspect of the diffraction pattern: intensity of Bragg peaks of different kinds (long-range crystal orders), intensity of diffuse scattering (phonons and short-range lattice imperfections), peak shape (domain size). The results of this work demonstrate how UED data can provide new insights on the plethora of interactions between crystal lattice and electronic degrees of freedom. |
| 일반주제명 | Physics. |
| 언어 | 영어 |
| 바로가기 | 
: 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
