| LDR | | 00000nam u2200205 4500 |
| 001 | | 000000436546 |
| 005 | | 20200228144614 |
| 008 | | 200131s2019 ||||||||||||||||| ||eng d |
| 020 | |
▼a 9781085568630 |
| 035 | |
▼a (MiAaPQ)AAI13809600 |
| 040 | |
▼a MiAaPQ
▼c MiAaPQ
▼d 247004 |
| 082 | 0 |
▼a 620.11 |
| 100 | 1 |
▼a Liu, Gerui. |
| 245 | 10 |
▼a Nonlinear Optical Responses in Type-II Weyl Semimetals. |
| 260 | |
▼a [S.l.]:
▼b University of Pennsylvania.,
▼c 2019. |
| 260 | 1 |
▼a Ann Arbor:
▼b ProQuest Dissertations & Theses,
▼c 2019. |
| 300 | |
▼a 137 p. |
| 500 | |
▼a Source: Dissertations Abstracts International, Volume: 81-02, Section: B. |
| 500 | |
▼a Advisor: Agarwal, Ritesh. |
| 502 | 1 |
▼a Thesis (Ph.D.)--University of Pennsylvania, 2019. |
| 506 | |
▼a This item must not be sold to any third party vendors. |
| 520 | |
▼a Weyl semimetals are gapless topological states of matter with broken inversion and/or time reversal symmetry. In this thesis, we will firstly discuss the observation of a novel photogalvanic effect in type-II Weyl semimetals including Td-MoTe2 Mo0.9W0.1Te2 and Mo0.3W0.7Te2. A circulating photocurrent is obtained under the illumination of normally incident light with circular polarization and the circulating current direction is opposite with different light helicity. Through temperature induced phase transition of MoTe2, this effect is further confirmed to exclusively occur in the Weyl phase. Since this CPGE current is controlled by the spatially varying beam profile, we define the effect as a spatially dispersive circular photogalvanic effect (sCPGE) and current amplitude is proven to be proportional to the beam gradient. By performing frequency-dependent measurements on the Weyl phase, we observe a sign reversal of sCPGE current at high energy excitation and low energy excitation. Our theoretical derivation shows that sCPGE is controlled by a unique symmetry selection rule related to asymmetric carrier excitation and relaxation, explaining the difference between Weyl phase and trivial phase as well as frequency dependent properties.Photoinduced anomalous Hall effect (AHE) is also observed in type-II Weyl semimetals. Longitudinal CPGE current is obtained under normally incident light while applying transverse bias, and the current magnitude is observed to be proportional to the bias voltage. Comparing the AHE conductivity in the 1T' phase and the Td phase of MoT2,e photoinduced AHE is found to be much more significant in Weyl phase. This effect can be understood by symmetry arguments and is described by a Fermi surface modulation under the external electric field |
| 590 | |
▼a School code: 0175. |
| 650 | 4 |
▼a Materials science. |
| 690 | |
▼a 0794 |
| 710 | 20 |
▼a University of Pennsylvania.
▼b Materials Science and Engineering. |
| 773 | 0 |
▼t Dissertations Abstracts International
▼g 81-02B. |
| 773 | |
▼t Dissertation Abstract International |
| 790 | |
▼a 0175 |
| 791 | |
▼a Ph.D. |
| 792 | |
▼a 2019 |
| 793 | |
▼a English |
| 856 | 40 |
▼u http://www.riss.kr/pdu/ddodLink.do?id=T15490603
▼n KERIS
▼z 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
| 980 | |
▼a 202002
▼f 2020 |
| 990 | |
▼a ***1816162 |
| 991 | |
▼a E-BOOK |