상세정보
Export to Refworks부가기능
Majorana and Andreev Bound States in Semiconductor-Superconductor Nanostructures
상세 프로파일
| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Majorana and Andreev Bound States in Semiconductor-Superconductor Nanostructures. |
| 개인저자 | Liu, Chun-Xiao. |
| 단체저자명 | University of Maryland, College Park. Physics. |
| 발행사항 | [S.l.]: University of Maryland, College Park., 2018. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2018. |
| 형태사항 | 132 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-02B. Dissertation Abstract International |
| ISBN | 9781085588355 |
| 학위논문주기 | Thesis (Ph.D.)--University of Maryland, College Park, 2018. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-02, Section: B.
Advisor: Sau, Jay D. |
| 이용제한사항 | This item must not be sold to any third party vendors. |
| 요약 | Majorana bound states have been a topic of active research over the last decades. In the perspective of theoretical physics, Majorana bound states, which are their own antiparticles, are zero-energy quasi-particle excitations in exotic superconductive systems. From a technological perspective, Majorana bound states can be utilized for the implementation of fault-tolerant quantum computation due to their topological properties. For example, two well-separated Majorana bound states can form a fermionic qubit state, the quantum information of its occupancy is stored in a nonlocal way, being robust against local decoherence. Also since Majorana bound states obey non-Abelian statistics, quantum gates can be implemented by braiding. Such gate operations are robust because small deviations in braiding trajectories do not affect the braiding results.So far the most promising platform for the realization of Majorana bound states is the one-dimensional semiconductor-superconductor nanostructures. The hallmark of the existence of Majorana bound states in such systems is a quantized zero-bias conductance peak in the tunneling spectroscopy for a normal-metal-superconductor junction. Although quantized zero-bias conductance peaks thatresemble the theoretical prediction have been observed in several experimental measurements, confusing aspects of the data muddy the conclusion. One source of confusion results from the existence of another type of excitation in these systems, i.e., the topologically trivial near-zero-energy Andreev bound states. These excitations mimic many behaviors of the topological Majorana bound states. In this thesis, we first investigate the tunnel spectrsocopy signatures of both Majorana and Andreev bound states. Then we discuss multiple proposals for differentiating between Majorana and Andreev bound states.In Chapter 1, we give an overview for Majorana bound states in the context of both spinless p-wave superconductors and spin-orbit coupled nanowires in proximity with an s-wave superconductor. We also show how the existence of a zero-energy Majorana bound state leads to a quantized zero-bias conductance peak in tunneling spectroscopy at zero temperature. In Chapter 2, we discuss possible physical mechanisms responsible for the discrepancy between minimal theory of Majorana nanowire and real experimental observations. Specifically, we focus on the effect of dissipation inside the heterostructure. In Chapter 3, we show that a near-zero-energy Andreev bound state may arise quite generically in the semiconductor-superconductor nanowire in the presence of a smooth variation in chemical potential. Although such Andreev bound states are topologically trivial, they mimic the behaviors of the topological Majorana bound states in many aspects. In Chapter 4, we discuss multiple proposals for distinguishing between trivial Andreev bound states and topological Majorana bound states in the normal-metal-superconductor junction. In Chapter 5, we discuss a proposal for future experiments, i.e., a normal-superconductor-normal junction for a Coulomb blockaded superconductor. In this proposal, one can directly measure the topological invariant of the bulk superconductor. Finally Chapter 6 concludes the thesis. |
| 일반주제명 | Condensed matter physics. Nanotechnology. |
| 언어 | 영어 |
| 바로가기 | 
: 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
