1
|
Zheng Z, Ma Q, Bi Z, de la Barrera S, Liu MH, Mao N, Zhang Y, Kiper N, Watanabe K, Taniguchi T, Kong J, Tisdale WA, Ashoori R, Gedik N, Fu L, Xu SY, Jarillo-Herrero P. Unconventional ferroelectricity in moiré heterostructures. Nature 2020; 588:71-76. [DOI: 10.1038/s41586-020-2970-9] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 10/07/2020] [Indexed: 11/09/2022]
|
2
|
Yamada S, Fujimoto A, Hidaka S, Akabori M, Imanaka Y, Takehana K. Fractional quantum Hall effects in In 0.75Ga 0.25As bilayer electron systems observed as "Finger print". Sci Rep 2019; 9:7446. [PMID: 31092854 PMCID: PMC6520355 DOI: 10.1038/s41598-019-43290-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 04/03/2019] [Indexed: 11/10/2022] Open
Abstract
Observations of fractional quantum Hall (FQH) plateaus are reported in bilayer electron gas system in wide (>80 nm) In0.75Ga0.25As wells. Several q/p (p = 5, 3, and 2, q > 5) QH states are confirmed at high temperatures (~1.6 K) when the critical conditions including an electron density imbalance as well as a dynamical resistance behavior at the bilayer-monolayer transition are properly satisfied. The former leads to a quantum limit in either of the layers and the latter might bring a meta-stable nature into FQH phenomena. Such a behavior occurs as a probability process associating with impurities or defects in the wells, they inevitably reflect the local structural landscapes of each sample. This is verified by the new finding that the kinds of fractional plateaus (what set of fractional filling factors) appeared are different depending on the samples, that is, they are the "finger print" in each sample.
Collapse
Affiliation(s)
- Syoji Yamada
- Osaka Institute of Technology, 5-16-1, Omiya, Asahi-ku Osaka, 535-8585, Japan.
| | - Akira Fujimoto
- Osaka Institute of Technology, 5-16-1, Omiya, Asahi-ku Osaka, 535-8585, Japan
| | - Siro Hidaka
- LT Center, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Masashi Akabori
- Japan Advanced Institute of Science and Technology, 1-1, Asahidai, Nomi, Ishikawa, 923-1292, Japan
| | - Yasutaka Imanaka
- National Institute for Materials Science, 3-13, Sakura, Tsukuba, Ibaraki, 305-0003, Japan
| | - Kanji Takehana
- National Institute for Materials Science, 3-13, Sakura, Tsukuba, Ibaraki, 305-0003, Japan
| |
Collapse
|
3
|
Jo I, Deng H, Liu Y, Pfeiffer LN, West KW, Baldwin KW, Shayegan M. Cyclotron Orbits of Composite Fermions in the Fractional Quantum Hall Regime. PHYSICAL REVIEW LETTERS 2018; 120:016802. [PMID: 29350938 DOI: 10.1103/physrevlett.120.016802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Indexed: 06/07/2023]
Abstract
We study a bilayer GaAs hole system that hosts two distinct many-body phases at low temperatures and high perpendicular magnetic fields. The higher-density (top) layer develops a Fermi sea of composite fermions (CFs) in its half-filled lowest Landau level, while the lower-density (bottom) layer forms a Wigner crystal (WC) as its filling becomes very small. Owing to the interlayer interaction, the CFs in the top layer feel the periodic Coulomb potential of the WC in the bottom layer. We measure the magnetoresistance of the top layer while changing the bottom-layer density. As the WC layer density increases, the resistance peaks separating the adjacent fractional quantum Hall states in the top layer change nonmonotonically and attain maximum values when the cyclotron orbit of the CFs encloses one WC lattice point. These features disappear at T=275 mK when the WC melts. The observation of such geometric resonance features is unprecedented and surprising as it implies that the CFs retain a well-defined cyclotron orbit and Fermi wave vector even deep in the fractional quantum Hall regime, far from half-filling.
Collapse
Affiliation(s)
- Insun Jo
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Hao Deng
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Yang Liu
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - L N Pfeiffer
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - K W West
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - K W Baldwin
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - M Shayegan
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| |
Collapse
|
4
|
Fallahazad B, Movva HCP, Kim K, Larentis S, Taniguchi T, Watanabe K, Banerjee SK, Tutuc E. Shubnikov-de Haas Oscillations of High-Mobility Holes in Monolayer and Bilayer WSe_{2}: Landau Level Degeneracy, Effective Mass, and Negative Compressibility. PHYSICAL REVIEW LETTERS 2016; 116:086601. [PMID: 26967432 DOI: 10.1103/physrevlett.116.086601] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Indexed: 06/05/2023]
Abstract
We study the magnetotransport properties of high-mobility holes in monolayer and bilayer WSe_{2}, which display well defined Shubnikov-de Haas (SdH) oscillations, and quantum Hall states in high magnetic fields. In both mono- and bilayer WSe_{2}, the SdH oscillations and the quantum Hall states occur predominantly at even filling factors, evincing a twofold Landau level degeneracy. The Fourier transform analysis of the SdH oscillations in bilayer WSe_{2} reveals the presence of two subbands localized in the top or the bottom layer, as well as negative compressibility. From the temperature dependence of the SdH oscillations we determine a hole effective mass of 0.45m_{0} for both mono- and bilayer WSe_{2}.
Collapse
Affiliation(s)
- Babak Fallahazad
- Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758, USA
| | - Hema C P Movva
- Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758, USA
| | - Kyounghwan Kim
- Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758, USA
| | - Stefano Larentis
- Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758, USA
| | - Takashi Taniguchi
- National Institute of Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan
| | - Kenji Watanabe
- National Institute of Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan
| | - Sanjay K Banerjee
- Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758, USA
| | - Emanuel Tutuc
- Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758, USA
| |
Collapse
|
5
|
Davies AG, Barnes CH, Zolleis KR, Nicholls JT, Simmons MY, Ritchie DA. Hybridization of single- and double-layer behavior in a double-quantum-well structure. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R17331-R17334. [PMID: 9985950 DOI: 10.1103/physrevb.54.r17331] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
6
|
Radtke RJ, Tamborenea PI. Spin instabilities in coupled semiconductor quantum wells. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:13832-13858. [PMID: 9985301 DOI: 10.1103/physrevb.54.13832] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|