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Emergent Phenomena and Applications in Artificially Stacked 2D Materials
Emergent Phenomena and Applications in Artificially Stacked 2D Materials
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20250211152807
- ISBN
- 9798384094531
- DDC
- 530
- 저자명
- Zhang, Yinong.
- 서명/저자
- Emergent Phenomena and Applications in Artificially Stacked 2D Materials
- 발행사항
- [Sl] : University of Washington, 2024
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2024
- 형태사항
- 142 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 86-03, Section: B.
- 주기사항
- Advisor: Xu, Xiaodong.
- 학위논문주기
- Thesis (Ph.D.)--University of Washington, 2024.
- 초록/해제
- 요약Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) possess broken inversion symmetry and strong spin-orbit coupling, leading to unique spin-valley locking effect. In TMD multilayers, rich excitonic responses are identified from the direct-to-indirect bandgap transition, where the coupling among spin, valley and layer pseudospin plays a crucial role in forming bright and dark exciton species and their complex hybridizations. Furthermore, structural engineering can be leveraged in building Rhombohedral (R) and Hexagonal (H) stacking orders and forming moire superlattice that further modulate the band structure and give rise to exotic physics. In this thesis, we first demonstrate the photoluminescence and reflectance spectra under varying doping densities and electric fields while increasing TMD layer thickness, to explain the bandgap transition. We further show that the spin-valley locking in H-stacked multilayer TMD yields an electronic superlattice structure, where alternating layers correspond to barriers and quantum wells, respectively, depending on the spin-valley indices and that the spin-valley locked superlattice hosts a kind of dipolar excitons with the electron and hole constituents separated in an every-other-layer configuration. Such excitons become optically bright via hybridization with intralayer excitons. This effect is also manifested by the presence of multiple anti-crossing patterns in the reflectance spectra, as the dipolar exciton is tuned through the intralayer resonance by an electric field. As layer thickness keeps increasing, the dipolar exciton can form one-dimensional Bose-Hubbard chain displaying a layer number dependent fine spectroscopy structures. In the next chapter, we identify the interfacial ferroelectricity in R-stacked twisted TMD. We perform scanning probe imaging to directly visualize the alternating domain polarizations. Optical spectroscopy of ABBA-twisted double bilayer TMD under varying out-of-plane electric fields reveals rich excitonic responses, among which the inter-bilayer excitons are coupled with local domain polarizations and result in built-in electric fields. Weak hysteresis loop of the inter-bilayer excitons' emissions is observed while sweeping the external electric field at opposite directions, and confirms the domain wall dynamics dictated by the interfacial ferroelectricity. Finally, in the last chapter, we report the observation of exciton hybridizations coupled with interfacial ferroelectricity in R-stacked twisted bilayer WSe2 systems, where dipolar excitons are allowed due to the matched spin-valley index and can hybridize with certain intralayer A exciton branches through an electron hopping process, which also makes them optically bright. Combining the built-in electric fields, we reconstruct the hybridization behaviors that are coupled with the interfacial ferroelectricity from the R-stacked moire interface. Furthermore, ferromagnetism and correlated states are identified in the same system through magneto-optic effect. Our results demonstrate the delicate coupling between the excitonic responses and the artificially stacked 2D materials and reveal exciting and exotic physical phenomena.
- 일반주제명
- Condensed matter physics
- 일반주제명
- Quantum physics
- 일반주제명
- Materials science
- 일반주제명
- Analytical chemistry
- 키워드
- Exciton
- 키워드
- Ferroelectricity
- 키워드
- Ferromagnetism
- 키워드
- Spectroscopy
- 기타저자
- University of Washington Physics
- 기본자료저록
- Dissertations Abstracts International. 86-03B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
008250123s2024 us c eng d■001000017163902
■00520250211152807
■006m o d
■007cr#unu||||||||
■020 ▼a9798384094531
■035 ▼a(MiAaPQ)AAI31557290
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a530
■1001 ▼aZhang, Yinong.
■24510▼aEmergent Phenomena and Applications in Artificially Stacked 2D Materials
■260 ▼a[Sl]▼bUniversity of Washington▼c2024
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2024
■300 ▼a142 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 86-03, Section: B.
■500 ▼aAdvisor: Xu, Xiaodong.
■5021 ▼aThesis (Ph.D.)--University of Washington, 2024.
■520 ▼aTwo-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) possess broken inversion symmetry and strong spin-orbit coupling, leading to unique spin-valley locking effect. In TMD multilayers, rich excitonic responses are identified from the direct-to-indirect bandgap transition, where the coupling among spin, valley and layer pseudospin plays a crucial role in forming bright and dark exciton species and their complex hybridizations. Furthermore, structural engineering can be leveraged in building Rhombohedral (R) and Hexagonal (H) stacking orders and forming moire superlattice that further modulate the band structure and give rise to exotic physics. In this thesis, we first demonstrate the photoluminescence and reflectance spectra under varying doping densities and electric fields while increasing TMD layer thickness, to explain the bandgap transition. We further show that the spin-valley locking in H-stacked multilayer TMD yields an electronic superlattice structure, where alternating layers correspond to barriers and quantum wells, respectively, depending on the spin-valley indices and that the spin-valley locked superlattice hosts a kind of dipolar excitons with the electron and hole constituents separated in an every-other-layer configuration. Such excitons become optically bright via hybridization with intralayer excitons. This effect is also manifested by the presence of multiple anti-crossing patterns in the reflectance spectra, as the dipolar exciton is tuned through the intralayer resonance by an electric field. As layer thickness keeps increasing, the dipolar exciton can form one-dimensional Bose-Hubbard chain displaying a layer number dependent fine spectroscopy structures. In the next chapter, we identify the interfacial ferroelectricity in R-stacked twisted TMD. We perform scanning probe imaging to directly visualize the alternating domain polarizations. Optical spectroscopy of ABBA-twisted double bilayer TMD under varying out-of-plane electric fields reveals rich excitonic responses, among which the inter-bilayer excitons are coupled with local domain polarizations and result in built-in electric fields. Weak hysteresis loop of the inter-bilayer excitons' emissions is observed while sweeping the external electric field at opposite directions, and confirms the domain wall dynamics dictated by the interfacial ferroelectricity. Finally, in the last chapter, we report the observation of exciton hybridizations coupled with interfacial ferroelectricity in R-stacked twisted bilayer WSe2 systems, where dipolar excitons are allowed due to the matched spin-valley index and can hybridize with certain intralayer A exciton branches through an electron hopping process, which also makes them optically bright. Combining the built-in electric fields, we reconstruct the hybridization behaviors that are coupled with the interfacial ferroelectricity from the R-stacked moire interface. Furthermore, ferromagnetism and correlated states are identified in the same system through magneto-optic effect. Our results demonstrate the delicate coupling between the excitonic responses and the artificially stacked 2D materials and reveal exciting and exotic physical phenomena.
■590 ▼aSchool code: 0250.
■650 4▼aCondensed matter physics
■650 4▼aQuantum physics
■650 4▼aMaterials science
■650 4▼aAnalytical chemistry
■653 ▼aExciton
■653 ▼aFerroelectricity
■653 ▼aFerromagnetism
■653 ▼aSpectroscopy
■653 ▼aTransition metal dichalcogenides
■653 ▼aTwo-dimensional materials
■690 ▼a0611
■690 ▼a0794
■690 ▼a0599
■690 ▼a0486
■71020▼aUniversity of Washington▼bPhysics.
■7730 ▼tDissertations Abstracts International▼g86-03B.
■790 ▼a0250
■791 ▼aPh.D.
■792 ▼a2024
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17163902▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
