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Understanding Correlated Insulating Ground States of Magic-Angle Twisted Bilayer Graphene- [electronic resource]
Understanding Correlated Insulating Ground States of Magic-Angle Twisted Bilayer Graphene- [electronic resource]
상세정보
- 자료유형
- 학위논문파일 국외
- 최종처리일시
- 20240214101655
- ISBN
- 9798380369190
- DDC
- 530
- 서명/저자
- Understanding Correlated Insulating Ground States of Magic-Angle Twisted Bilayer Graphene - [electronic resource]
- 발행사항
- [S.l.]: : University of California, Berkeley., 2023
- 발행사항
- Ann Arbor : : ProQuest Dissertations & Theses,, 2023
- 형태사항
- 1 online resource(129 p.)
- 주기사항
- Source: Dissertations Abstracts International, Volume: 85-03, Section: B.
- 주기사항
- Advisor: Zaletel, Michael.
- 학위논문주기
- Thesis (Ph.D.)--University of California, Berkeley, 2023.
- 사용제한주기
- This item must not be sold to any third party vendors.
- 초록/해제
- 요약When two layers of graphene are put on top of each another with a relative twist, their lattice mismatch gives rise to a moire pattern. When the twist angle is near 1.1 degrees, a so-called magic angle, the band structure of twisted bilayer graphene becomes extremely flat around the Fermi energy, enhancing the effect of electron-electron interaction. Remarkably, magic-angle twisted bilayer graphene (MATBG) becomes superconducting at low temperatures. The origin of this superconducting behavior remains elusive.Curiously, the superconducting behavior is usually accompanied by correlated insulating behavior in nearby parameter regions in the phase diagram. These correlated insulators cannot be described by non-interacting band theory, hinting at the importance of electron-electron interaction.In this thesis, we attempt to understand these correlated insulators by a combination of numerical and analytical techniques. On the numerical side, we will utilize the density-matrix renormalization group (DMRG) extensively to obtain the ground states of MATBG. Owing to the complexity of the problem, this required us to develop a non-trivial routine for encoding the Hamiltonian. We find that DMRG often reproduces the findings from Hartree-Fock simulations. On the analytical side, we aim to understand different symmetry-breaking states of MATBG. Based on symmetry analysis, we propose using scanning tunneling microscopy (STM) to distinguish between different candidate ground states, and test our analytical prediction using numerical simulation.Taken together, this thesis represents a significant step toward understanding the correlated insulating behavior of MATBG.
- 일반주제명
- Physical chemistry.
- 일반주제명
- Materials science.
- 키워드
- Density-matrix
- 기타저자
- University of California, Berkeley Physics
- 기본자료저록
- Dissertations Abstracts International. 85-03B.
- 기본자료저록
- Dissertation Abstract International
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■00520240214101655
■006m o d
■007cr#unu||||||||
■020 ▼a9798380369190
■035 ▼a(MiAaPQ)AAI30634847
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a530
■1001 ▼aSoejima, Tomohiro.
■24510▼aUnderstanding Correlated Insulating Ground States of Magic-Angle Twisted Bilayer Graphene▼h[electronic resource]
■260 ▼a[S.l.]:▼bUniversity of California, Berkeley. ▼c2023
■260 1▼aAnn Arbor :▼bProQuest Dissertations & Theses, ▼c2023
■300 ▼a1 online resource(129 p.)
■500 ▼aSource: Dissertations Abstracts International, Volume: 85-03, Section: B.
■500 ▼aAdvisor: Zaletel, Michael.
■5021 ▼aThesis (Ph.D.)--University of California, Berkeley, 2023.
■506 ▼aThis item must not be sold to any third party vendors.
■520 ▼aWhen two layers of graphene are put on top of each another with a relative twist, their lattice mismatch gives rise to a moire pattern. When the twist angle is near 1.1 degrees, a so-called magic angle, the band structure of twisted bilayer graphene becomes extremely flat around the Fermi energy, enhancing the effect of electron-electron interaction. Remarkably, magic-angle twisted bilayer graphene (MATBG) becomes superconducting at low temperatures. The origin of this superconducting behavior remains elusive.Curiously, the superconducting behavior is usually accompanied by correlated insulating behavior in nearby parameter regions in the phase diagram. These correlated insulators cannot be described by non-interacting band theory, hinting at the importance of electron-electron interaction.In this thesis, we attempt to understand these correlated insulators by a combination of numerical and analytical techniques. On the numerical side, we will utilize the density-matrix renormalization group (DMRG) extensively to obtain the ground states of MATBG. Owing to the complexity of the problem, this required us to develop a non-trivial routine for encoding the Hamiltonian. We find that DMRG often reproduces the findings from Hartree-Fock simulations. On the analytical side, we aim to understand different symmetry-breaking states of MATBG. Based on symmetry analysis, we propose using scanning tunneling microscopy (STM) to distinguish between different candidate ground states, and test our analytical prediction using numerical simulation.Taken together, this thesis represents a significant step toward understanding the correlated insulating behavior of MATBG.
■590 ▼aSchool code: 0028.
■650 4▼aCondensed matter physics.
■650 4▼aPhysical chemistry.
■650 4▼aMaterials science.
■653 ▼aStrongly correlated electrons
■653 ▼aSuperconductivity
■653 ▼aTwisted bilayer graphene
■653 ▼aDensity-matrix
■653 ▼aScanning tunneling microscopy
■690 ▼a0611
■690 ▼a0794
■690 ▼a0494
■71020▼aUniversity of California, Berkeley▼bPhysics.
■7730 ▼tDissertations Abstracts International▼g85-03B.
■773 ▼tDissertation Abstract International
■790 ▼a0028
■791 ▼aPh.D.
■792 ▼a2023
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T16934796▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
■980 ▼a202402▼f2024
