1
|
Jaskólski W. Metal-Semiconductor Behavior along the Line of Stacking Order Change in Gated Multilayer Graphene. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1915. [PMID: 38673272 PMCID: PMC11051715 DOI: 10.3390/ma17081915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/12/2024] [Accepted: 04/19/2024] [Indexed: 04/28/2024]
Abstract
We investigated gated multilayer graphene with stacking order changes along the armchair direction. We consider that some layers cracked to release shear strain at the stacking domain wall. The energy cones of graphene overlap along the corresponding direction in the k-space, so the topological gapless states from different valleys also overlap. However, these states strongly interact and split due to atomic-scale defects caused by the broken layers, yielding an effective energy gap. We find that for some gate voltages, the gap states cross and the metallic behavior along the stacking domain wall can be restored. In particular cases, a flat band appears at the Fermi energy. We show that for small variations in the gate voltage, the charge occupying this band oscillates between the outer layers.
Collapse
Affiliation(s)
- Włodzimierz Jaskólski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziądzka 5, 87-100 Toruń, Poland
| |
Collapse
|
2
|
Wang S, Song J, Sun M, Cao S. Emerging Characteristics and Properties of Moiré Materials. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2881. [PMID: 37947726 PMCID: PMC10649551 DOI: 10.3390/nano13212881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 10/26/2023] [Accepted: 10/29/2023] [Indexed: 11/12/2023]
Abstract
In recent years, scientists have conducted extensive research on Moiré materials and have discovered some compelling properties. The Moiré superlattice allows superconductivity through flat-band and strong correlation effects. The presence of flat bands causes the Moiré material to exhibit topological properties as well. Modulating electronic interactions with magnetic fields in Moiré materials enables the fractional quantum Hall effect. In addition, Moiré materials have ferromagnetic and antiferromagnetic properties. By tuning the interlayer coupling and spin interactions of the Moiré superlattice, different magnetic properties can be achieved. Finally, this review also discusses the applications of Moiré materials in the fields of photocurrent, superconductivity, and thermoelectricity. Overall, Moiré superlattices provide a new dimension in the development of two-dimensional materials.
Collapse
Affiliation(s)
- Shaofeng Wang
- School of Physics, Liaoning University, Shenyang 110036, China
| | - Jizhe Song
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China;
| | - Mengtao Sun
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China;
| | - Shuo Cao
- School of Physics, Liaoning University, Shenyang 110036, China
| |
Collapse
|
3
|
Mesple F, Walet NR, Trambly de Laissardière G, Guinea F, Došenović D, Okuno H, Paillet C, Michon A, Chapelier C, Renard VT. Giant Atomic Swirl in Graphene Bilayers with Biaxial Heterostrain. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2306312. [PMID: 37615204 DOI: 10.1002/adma.202306312] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/10/2023] [Indexed: 08/25/2023]
Abstract
The study of moiré engineering started with the advent of van der Waals heterostructures, in which stacking 2D layers with different lattice constants leads to a moiré pattern controlling their electronic properties. The field entered a new era when it was found that adjusting the twist between two graphene layers led to strongly-correlated-electron physics and topological effects associated with atomic relaxation. A twist is now routinely used to adjust the properties of 2D materials. This study investigates a new type of moiré superlattice in bilayer graphene when one layer is biaxially strained with respect to the other-so-called biaxial heterostrain. Scanning tunneling microscopy measurements uncover spiraling electronic states associated with a novel symmetry-breaking atomic reconstruction at small biaxial heterostrain. Atomistic calculations using experimental parameters as inputs reveal that a giant atomic swirl forms around regions of aligned stacking to reduce the mechanical energy of the bilayer. Tight-binding calculations performed on the relaxed structure show that the observed electronic states decorate spiraling domain wall solitons as required by topology. This study establishes biaxial heterostrain as an important parameter to be harnessed for the next step of moiré engineering in van der Waals multilayers.
Collapse
Affiliation(s)
- Florie Mesple
- Univ. Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, Grenoble, 38000, France
| | - Niels R Walet
- Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PY, UK
| | - Guy Trambly de Laissardière
- Laboratoire de Physique Théorique et Modélisation (UMR 8089), CY Cergy Paris Université, CNRS, Cergy-Pontoise, 95302, France
| | - Francisco Guinea
- Imdea Nanoscience, Faraday 9, Madrid, 28015, Spain
- Donostia International Physics Center, Paseo Manuel de Lardizábal 4, San Sebastián, 20018, Spain
| | | | - Hanako Okuno
- University Grenoble Alpes, CEA, IRIG-MEM, Grenoble, 38054, France
| | - Colin Paillet
- Université Côte d'Azur, CNRS, CRHEA, Rue Bernard Grégory, Valbonne, 06560, France
| | - Adrien Michon
- Université Côte d'Azur, CNRS, CRHEA, Rue Bernard Grégory, Valbonne, 06560, France
| | - Claude Chapelier
- Univ. Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, Grenoble, 38000, France
| | - Vincent T Renard
- Univ. Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, Grenoble, 38000, France
| |
Collapse
|
4
|
Geisenhof FR, Winterer F, Seiler AM, Lenz J, Zhang F, Weitz RT. Impact of Electric Field Disorder on Broken-Symmetry States in Ultraclean Bilayer Graphene. NANO LETTERS 2022; 22:7378-7385. [PMID: 36113049 DOI: 10.1021/acs.nanolett.2c02119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Bilayer graphene (BLG) has multiple internal degrees of freedom and a constant density of states down to the charge neutrality point when trigonal warping is ignored. Consequently, it is susceptible to various competing ground states. However, a coherent experimental determination of the ground state has been challenging due to the interaction-disorder interplay. Here we present an extensive transport study in a series of dually gated freestanding BLG devices and identify the layer-antiferromagnet as the ground state with a continuous strength across all devices. This strength correlates with the width of the state in the electric field. We systematically identify electric-field disorder─spatial variations in the interlayer potential difference─as the main source responsible for the observations. Our results pinpoint for the first time the importance of electric-field disorder on spontaneous symmetry breaking in BLG and solve a long-standing debate on its ground state. The electric-field disorder should be universal to all 2D materials.
Collapse
Affiliation(s)
- Fabian R Geisenhof
- Physics of Nanosystems, Department of Physics, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, Munich 80539, Germany
| | - Felix Winterer
- Physics of Nanosystems, Department of Physics, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, Munich 80539, Germany
| | - Anna M Seiler
- Physics of Nanosystems, Department of Physics, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, Munich 80539, Germany
- 1st Physical Institute, Faculty of Physics, University of Göttingen, Friedrich-Hund-Platz 1, Göttingen 37077, Germany
| | - Jakob Lenz
- Physics of Nanosystems, Department of Physics, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, Munich 80539, Germany
| | - Fan Zhang
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - R Thomas Weitz
- Physics of Nanosystems, Department of Physics, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, Munich 80539, Germany
- Center for Nanoscience (CeNS), Schellingstrasse 4, Munich 80799, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstrasse 4, Munich 80799, Germany
- 1st Physical Institute, Faculty of Physics, University of Göttingen, Friedrich-Hund-Platz 1, Göttingen 37077, Germany
| |
Collapse
|
5
|
An Q, Moutanabbir O, Guo H. Moiré patterns of twisted bilayer antimonene and their structural and electronic transition. NANOSCALE 2021; 13:13427-13436. [PMID: 34477748 DOI: 10.1039/d1nr02843j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Interlayer twisting in two-dimensional (2D) van der Waals (vdW) heterostructures often leads to a periodic moiré pattern which is a superlattice structure on top of the original atomic lattice of the 2D layers. The formation of a moiré superlattice can be accompanied by a significant structural reconstruction and ultra-flat electronic bands. The moiré superlattice is typically built with a tunable scale by controlling the rotation angle θ between the individual 2D layers. In this paper, we report the structural reconstruction and electronic transition in moiré patterns of twisted bilayer antimonene, based on Kohn-Sham density functional theory calculations. Starting from rigid moiré structures, the atomic relaxation leads to an array of high-symmetry stacking domains with soliton boundaries through a vortex-like reconstruction. For twist angle θ≤ 6.01°, the impact of the structural reconstruction on the electronic bands becomes very significant, in the appearance of flat bands at the valence band edge, and no magic angle is required for the flat bands to appear in the 2D Sb moiré patterns. Both inhomogeneous interlayer hybridization and local strain are found to be responsible for the formation of these flat electronic bands.
Collapse
Affiliation(s)
- Qi An
- Department of Physics, McGill University, 3600 Rue University, Montréal, Québec H3A 2 T8, Canada.
| | | | | |
Collapse
|
6
|
Ahmed I, Shuai Y, Rafique M, Mahar MA, Larik AS. Tailoring spintronic and opto-electronic characteristics of bilayer AlN through MnO x clusters intercalation; an ab initio study. RSC Adv 2021; 11:15167-15176. [PMID: 35424022 PMCID: PMC8698386 DOI: 10.1039/d1ra01532j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/14/2021] [Indexed: 11/21/2022] Open
Abstract
Adopting ab initio density functional theory (DFT) technique, the spintronic and opto-electronic characteristics of MnO x (i.e., Mn, MnO, MnO2, MnO3 and MnO4) clusters intercalated bilayer AlN (BL/AlN) systems are investigated in this paper. In terms of electron transfer, charge transfer occurs from BL/AlN to the MnO x clusters. MnO x clusters intercalation induces magnetic behavior in the non-magnetic AlN system. The splitting of electronic bands occurs, thus producing spintronic trends in the electronic structure of BL/AlN system. Further, MnO x intercalation converts insulating BL/AlN to a half metal/semiconductor material during spin up/down bands depending upon the type of impurity cluster present in its lattice. For instance, Mn, MnO and MnO2 intercalation in BL/AlN produces a half metallic BL/AlN system as surface states are available at the Fermi Energy (E F) level for spin up and down band channels, accordingly. Whereas, MnO3 and MnO4 intercalation produces a conducting BL/AlN system having a 0.5 eV and 0.6 eV band gap during the spin down band channel, respectively. During spin up band channels these systems behave as semiconductors with band gaps of 1.4 eV and 1.2 eV, respectively. In terms of optical characteristics (i.e., absorption coefficient, reflectivity and energy loss spectrum (ELS)), it was found that MnO x intercalation improves the absorption spectrum in the low electron energy range and absorption peaks are observed in the 0-3 eV energy range, which are not present in the absorption spectrum of pure BL/AlN. The static reflectivity parameter of BL/AlN is increased after MnO x intercalation and the ELS parameter obtains significant peak intensities in the 0-2 eV energy range, whereas for pure BL/AlN, ELS contains negligible value in this energy range. Outcomes of this study indicate that, MnO x clusters intercalation in BL/AlN is a suitable technique to tailor its spintronic and opto-electronic trends. Thus, experimental investigation can be carried out on the systems discussed in this work, so as to fabricate practical layered AlN systems that are functional in the field of nano-technology.
Collapse
Affiliation(s)
- Irfan Ahmed
- Mehran University of Engineering and Technology, SZAB Campus, Khairpur Mirs' Pakistan
| | - Yong Shuai
- School of Energy Science and Engineering, Harbin Institute of Technology 92 West Dazhi Street Harbin 150001 PR China
| | - Muhammad Rafique
- Mehran University of Engineering and Technology, SZAB Campus, Khairpur Mirs' Pakistan
- School of Energy Science and Engineering, Harbin Institute of Technology 92 West Dazhi Street Harbin 150001 PR China
| | - Mukhtiar Ahmed Mahar
- Mehran University of Engineering and Technology, SZAB Campus, Khairpur Mirs' Pakistan
- Mehran University of Engineering and Technology Jamshoro Sindh Pakistan
| | - Abdul Sattar Larik
- Mehran University of Engineering and Technology, SZAB Campus, Khairpur Mirs' Pakistan
- Mehran University of Engineering and Technology Jamshoro Sindh Pakistan
| |
Collapse
|
7
|
Khan MF, Rehman S, Rehman MA, Basit MA, Kim DK, Ahmed F, Khalil HMW, Akhtar I, Jun SC. Modulation of Magnetoresistance Polarity in BLG/SL-MoSe 2 Heterostacks. NANOSCALE RESEARCH LETTERS 2020; 15:136. [PMID: 32572648 PMCID: PMC7310050 DOI: 10.1186/s11671-020-03365-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 06/07/2020] [Indexed: 06/01/2023]
Abstract
Two-dimensional (2D) layered materials have an atomically thin and flat nature which makes it an ultimate candidate for spintronic devices. The spin-valve junctions (SVJs), composed of 2D materials, have been recognized as unique features of spin transport polarization. However, the magnetotransport properties of SVJs are highly influenced by the type of intervening layer (spacer) inserted between the ferromagnetic materials (FMs). In this situation, the spin filtering effect at the interfaces plays a critical role in the observation of the magnetoresistance (MR) of such magnetic structures, which can be improved by using promising hybrid structure. Here, we report MR of bilayer graphene (BLG), single-layer MoSe2 (SL-MoSe2), and BLG/SL-MoSe2 heterostack SVJs. However, before annealing, BLG and SL-MoSe2 SVJs demonstrate positive MR, but after annealing, BLG reverses its polarity while the SL-MoSe2 maintains its polarity and demonstrated stable positive spin polarizations at both interfaces due to meager doping effect of ferromagnetic (FM) contacts. Further, Co/BLG/SL-MoSe2/NiFe determines positive MR, i.e., ~ 1.71% and ~ 1.86% at T = 4 K before and after annealing, respectively. On the contrary, NiFe/BLG/SL-MoSe2/Co SVJs showed positive MR before annealing and subsequently reversed its MR sign after annealing due to the proximity-induced effect of metals doping with graphene. The obtained results can be useful to comprehend the origin of polarity and the selection of non-magnetic material (spacer) for magnetotransport properties. Thus, this study established a new paragon for novel spintronic applications.
Collapse
Affiliation(s)
- Muhammad Farooq Khan
- Department of Electrical Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul, 05006, South Korea
| | - Shania Rehman
- Department of Electrical Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul, 05006, South Korea
| | - Malik Abdul Rehman
- School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, South Korea
| | - Muhammad Abdul Basit
- Department of Materials Science and Engineering, Institute of Space Technology, Islamabad, 44000, Pakistan
| | - Deok-Kee Kim
- Department of Electrical Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul, 05006, South Korea
| | - Faisal Ahmed
- Department of Mechanical Engineering, NUST College of Electrical and Mechanical Engineering, National University of Science and Technology, Islamabad, 44000, Pakistan
- Department of Electronics and Nanoengineering, Aalto University, P.O. Box 13500, F1-00076, Aalto, Finland
| | - H M Waseem Khalil
- Department of Electrical Engineering, College of Engineering and Technology, University of Sargodha, Sargodha, Pakistan
| | - Imtisal Akhtar
- Department of Mechanical Engineering, Chung-Ang University, Seoul, South Korea
| | - Seong Chan Jun
- School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, South Korea.
| |
Collapse
|
8
|
Lebedeva IV, Popov AM. Two Phases with Different Domain Wall Networks and a Reentrant Phase Transition in Bilayer Graphene under Strain. PHYSICAL REVIEW LETTERS 2020; 124:116101. [PMID: 32242692 DOI: 10.1103/physrevlett.124.116101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 02/21/2020] [Indexed: 06/11/2023]
Abstract
The analytical two-chain Frenkel-Kontorova model is used to describe domain wall networks in bilayer graphene upon biaxial stretching of one of the layers. We show that the commensurate-incommensurate phase transition leading to formation of a regular triangular domain wall network at the relative biaxial elongation of 3.0×10^{-3} is followed by the transition to another incommensurate phase with a striped network at the elongation of 3.7×10^{-3}. The reentrant transition to the phase with a triangular domain wall network is predicted for the elongation ∼10^{-2}.
Collapse
Affiliation(s)
| | - Andrey M Popov
- Institute for Spectroscopy of Russian Academy of Sciences, Troitsk, Moscow 108840, Russia
| |
Collapse
|
9
|
Park HJ, Cha J, Choi M, Kim JH, Tay RY, Teo EHT, Park N, Hong S, Lee Z. One-dimensional hexagonal boron nitride conducting channel. SCIENCE ADVANCES 2020; 6:eaay4958. [PMID: 32181347 PMCID: PMC7060069 DOI: 10.1126/sciadv.aay4958] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 12/12/2019] [Indexed: 05/16/2023]
Abstract
Hexagonal boron nitride (hBN) is an insulating two-dimensional (2D) material with a large bandgap. Although known for its interfacing with other 2D materials and structural similarities to graphene, the potential use of hBN in 2D electronics is limited by its insulating nature. Here, we report atomically sharp twin boundaries at AA'/AB stacking boundaries in chemical vapor deposition-synthesized few-layer hBN. We find that the twin boundary is composed of a 6'6' configuration, showing conducting feature with a zero bandgap. Furthermore, the formation mechanism of the atomically sharp twin boundaries is suggested by an analogy with stacking combinations of AA'/AB based on the observations of extended Klein edges at the layer boundaries of AB-stacked hBN. The atomically sharp AA'/AB stacking boundary is promising as an ultimate 1D electron channel embedded in insulating pristine hBN. This study will provide insights into the fabrication of single-hBN electronic devices.
Collapse
Affiliation(s)
- Hyo Ju Park
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Janghwan Cha
- Department of Physics, Graphene Research Institute, and GRI-TPC International Research Center, Sejong University, Seoul 05006, Republic of Korea
| | - Min Choi
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jung Hwa Kim
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Roland Yingjie Tay
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
- Temasek Laboratories@NTU, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Edwin Hang Tong Teo
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Noejung Park
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Suklyun Hong
- Department of Physics, Graphene Research Institute, and GRI-TPC International Research Center, Sejong University, Seoul 05006, Republic of Korea
- Corresponding author. (Z.L.); (S.H.)
| | - Zonghoon Lee
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
- Corresponding author. (Z.L.); (S.H.)
| |
Collapse
|
10
|
Jaskólski W, Ayuela A. Spin-layer locked gapless states in gated bilayer graphene. RSC Adv 2019; 9:42140-42144. [PMID: 35542834 PMCID: PMC9076544 DOI: 10.1039/c9ra07319a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 11/21/2019] [Indexed: 12/04/2022] Open
Abstract
Gated bilayer graphene exhibits spin-degenerate gapless states with a topological character localized at stacking domain walls. These states allow for one-dimensional currents along the domain walls. We herein demonstrate that these topologically protected currents are spin-polarized and locked in a single layer when bilayer graphene contains stacking domain walls decorated with magnetic defects. The magnetic defects, which we model as π-vacancies, perturb the topological states but also lift their spin degeneracy. One gapless state survives the perturbation of these defects, and its spin polarization is largely localized in one layer. The spin-polarized current in the topological state flows in a single layer, and this finding suggests the possibility of effectively exploiting these states in spintronic applications. Spin-degenerate gapless states with a topological character are spin-polarized and locked in a single layer when bilayer graphene contains stacking domain walls decorated with magnetic defects.![]()
Collapse
Affiliation(s)
- W Jaskólski
- Faculty of Physics, Astronomy and Informatics, Institute of Physics, Nicolaus Copernicus University Grudziadzka 5 87-100 Toruń Poland
| | - A Ayuela
- Donostia International Physics Center (DIPC) Manuel de Lardizabal 4 E-20018 San Sebastián Spain.,Centro de Física de Materiales-MPC CSIC-UPV/EHU Manuel de Lardizabal 5 E-20018 San Sebastián Spain
| |
Collapse
|
11
|
Kim JH, Kim SY, Cho Y, Park HJ, Shin HJ, Kwon SY, Lee Z. Interface-Driven Partial Dislocation Formation in 2D Heterostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1807486. [PMID: 30785234 DOI: 10.1002/adma.201807486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/18/2019] [Indexed: 06/09/2023]
Abstract
Van der Waals (vdW) epitaxy allows the fabrication of various heterostructures with dramatically released lattice matching conditions. This study demonstrates interface-driven stacking boundaries in WS2 using epitaxially grown tungsten disulfide (WS2 ) on wrinkled graphene. Graphene wrinkles function as highly reactive nucleation sites on WS2 epilayers; however, they impede lateral growth and induce additional stress in the epilayer due to anisotropic friction. Moreover, partial dislocation-driven in-plane strain facilitates out-of-plane buckling with a height of 1 nm to release in-plane strain. Remarkably, in-plane strain relaxation at partial dislocations restores the bandgap to that of monolayer WS2 due to reduced interlayer interaction. These findings clarify significant substrate morphology effects even in vdW epitaxy and are potentially useful for various applications involving modifying optical and electronic properties by manipulating extended 1D defects via substrate morphology control.
Collapse
Affiliation(s)
- Jung Hwa Kim
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Se-Yang Kim
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Yeonchoo Cho
- Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Hyo Ju Park
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
| | - Hyeon-Jin Shin
- Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Soon-Yong Kwon
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Zonghoon Lee
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
| |
Collapse
|
12
|
Naik MH, Jain M. Ultraflatbands and Shear Solitons in Moiré Patterns of Twisted Bilayer Transition Metal Dichalcogenides. PHYSICAL REVIEW LETTERS 2018; 121:266401. [PMID: 30636141 DOI: 10.1103/physrevlett.121.266401] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/26/2018] [Indexed: 05/25/2023]
Abstract
Ultraflatbands in twisted bilayers of two-dimensional materials have the potential to host strong correlations, including the Mott-insulating phase at half-filling of the band. Using first-principles density functional theory calculations, we show the emergence of ultraflatbands at the valence band edge in twisted bilayer MoS_{2}, a prototypical transition metal dichalcogenide. The computed band widths, 5 and 23 meV for 56.5° and 3.5° twist angles, respectively, are comparable to that of twisted bilayer graphene near "magic" angles. Large structural transformations in the moiré patterns lead to formation of shear solitons at stacking boundaries and strongly influence the electronic structure. We extend our analysis for twisted bilayer MoS_{2} to show that flatbands can occur at the valence band edge of twisted bilayer WS_{2}, MoSe_{2}, and WSe_{2} as well.
Collapse
Affiliation(s)
- Mit H Naik
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Manish Jain
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
| |
Collapse
|
13
|
Nam Y, Ki DK, Soler-Delgado D, Morpurgo AF. A family of finite-temperature electronic phase transitions in graphene multilayers. Science 2018; 362:324-328. [PMID: 30337406 DOI: 10.1126/science.aar6855] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 08/28/2018] [Indexed: 12/24/2022]
Abstract
Suspended Bernal-stacked graphene multilayers up to an unexpectedly large thickness exhibit a broken-symmetry ground state whose origin remains to be understood. We show that a finite-temperature second-order phase transition occurs in multilayers whose critical temperature (T c) increases from 12 kelvins (K) in bilayers to 100 K in heptalayers. A comparison of the data with a phenomenological model inspired by a mean-field approach suggests that the transition is associated with the appearance of a self-consistent valley- and spin-dependent staggered potential that changes sign from one layer to the next, appearing at T c and increasing upon cooling. The systematic evolution with thickness of several measured quantities imposes constraints on any microscopic theory aiming to analyze the nature of electronic correlations in this system.
Collapse
Affiliation(s)
- Youngwoo Nam
- Department of Quantum Matter Physics (DQMP) and Group of Applied Physics (GAP), University of Geneva, 24 Quai Ernest-Ansermet, CH1211 Genéve 4, Switzerland.,Department of Physics, Gyeongsang National University, Jinju-daero 501, Jinju-si, South Korea
| | - Dong-Keun Ki
- Department of Quantum Matter Physics (DQMP) and Group of Applied Physics (GAP), University of Geneva, 24 Quai Ernest-Ansermet, CH1211 Genéve 4, Switzerland.,Department of Physics, The University of Hong Kong, Hong Kong, China
| | - David Soler-Delgado
- Department of Quantum Matter Physics (DQMP) and Group of Applied Physics (GAP), University of Geneva, 24 Quai Ernest-Ansermet, CH1211 Genéve 4, Switzerland
| | - Alberto F Morpurgo
- Department of Quantum Matter Physics (DQMP) and Group of Applied Physics (GAP), University of Geneva, 24 Quai Ernest-Ansermet, CH1211 Genéve 4, Switzerland.
| |
Collapse
|
14
|
Schweizer P, Dolle C, Spiecker E. In situ manipulation and switching of dislocations in bilayer graphene. SCIENCE ADVANCES 2018; 4:eaat4712. [PMID: 30105305 PMCID: PMC6086622 DOI: 10.1126/sciadv.aat4712] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 06/29/2018] [Indexed: 05/02/2023]
Abstract
Topological defects in crystalline solids are of fundamental interest in physics and materials science because they can radically alter the properties of virtually any material. Of particular importance are line defects, known as dislocations, which are the main carriers of plasticity and have a tremendous effect on electronic and optical properties. Understanding and controlling the occurrence and behavior of those defects have been of major and ongoing interest since their discovery in the 1930s. This interest was renewed with the advent of two-dimensional materials in which a single topological defect can alter the functionality of the whole system and even create new physical phenomena. We present an experimental approach to directly manipulate dislocations in situ on the nanometer scale by using a dedicated scanning electron microscope setup. With this approach, key fundamental characteristics such as line tension, defect interaction, and node formation have been studied. A novel switching reaction, based on the recombination of dislocation lines, was found, which paves the way for the concept of switches made of a bimodal topological defect configuration.
Collapse
|
15
|
Jaskólski W, Pelc M, Bryant GW, Chico L, Ayuela A. Controlling the layer localization of gapless states in bilayer graphene with a gate voltage. 2D MATERIALS 2018; 5:10.1088/2053-1583/aaa490. [PMID: 32117572 PMCID: PMC7047727 DOI: 10.1088/2053-1583/aaa490] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Experiments in gated bilayer graphene with stacking domain walls present topological gapless states protected by no-valley mixing. Here we research these states under gate voltages using atomistic models, which allow us to elucidate their origin. We find that the gate potential controls the layer localization of the two states, which switches non-trivially between layers depending on the applied gate voltage magnitude. We also show how these bilayer gapless states arise from bands of single-layer graphene by analyzing the formation of carbon bonds between layers. Based on this analysis we provide a model Hamiltonian with analytical solutions, which explains the layer localization as a function of the ratio between the applied potential and interlayer hopping. Our results open a route for the manipulation of gapless states in electronic devices, analogous to the proposed writing and reading memories in topological insulators.
Collapse
Affiliation(s)
- W Jaskólski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Toruń, Poland
| | - M Pelc
- Donostia International Physics Center (DIPC), Paseo Manuel Lardizabal 4, 20018 Donostia-San Sebastián, Spain
- Centro de Física de Materiales, CFM-MPC CSIC-UPV/EHU, Paseo Manuel Lardizabal 5, 20018 Donostia-San Sebastián, Spain
| | - Garnett W Bryant
- Quantum Measurement Division and Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, MD, 20899-8423, United States of America
| | - Leonor Chico
- Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), C/ Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel Lardizabal 4, 20018 Donostia-San Sebastián, Spain
| | - A Ayuela
- Donostia International Physics Center (DIPC), Paseo Manuel Lardizabal 4, 20018 Donostia-San Sebastián, Spain
- Centro de Física de Materiales, CFM-MPC CSIC-UPV/EHU, Paseo Manuel Lardizabal 5, 20018 Donostia-San Sebastián, Spain
- Departamento de Física de Materiales, Facultad de Químicas, UPV-EHU, 20018 San Sebastián, Spain
| |
Collapse
|
16
|
Jiang BY, Ni GX, Addison Z, Shi JK, Liu X, Zhao SYF, Kim P, Mele EJ, Basov DN, Fogler MM. Plasmon Reflections by Topological Electronic Boundaries in Bilayer Graphene. NANO LETTERS 2017; 17:7080-7085. [PMID: 28967761 DOI: 10.1021/acs.nanolett.7b03816] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Domain walls separating regions of AB and BA interlayer stacking in bilayer graphene have attracted attention as novel examples of structural solitons, topological electronic boundaries, and nanoscale plasmonic scatterers. We show that strong coupling of domain walls to surface plasmons observed in infrared nanoimaging experiments is due to topological chiral modes confined to the walls. The optical transitions among these chiral modes and the band continua enhance the local conductivity, which leads to plasmon reflection by the domain walls. The imaging reveals two kinds of plasmonic standing-wave interference patterns, which we attribute to shear and tensile domain walls. We compute the electronic structure of both wall varieties and show that the tensile wall contains additional confined bands which produce a structure-specific contrast of the local conductivity, in agreement with the experiment. The coupling between the confined modes and the surface plasmon scattering unveiled in this work is expected to be common to other topological electronic boundaries found in van der Waals materials. This coupling provides a qualitatively new pathway toward controlling plasmons in nanostructures.
Collapse
Affiliation(s)
- Bor-Yuan Jiang
- Department of Physics, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Guang-Xin Ni
- Department of Physics, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, People's Republic of China
| | - Zachariah Addison
- Department of Physics & Astronomy, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Jing K Shi
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Xiaomeng Liu
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Shu Yang Frank Zhao
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Philip Kim
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Eugene J Mele
- Department of Physics & Astronomy, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Dimitri N Basov
- Department of Physics, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
- Department of Physics, Columbia University , New York, New York 10027, United States
| | - Michael M Fogler
- Department of Physics, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093, United States
| |
Collapse
|
17
|
Shallcross S, Sharma S, Weber HB. Anomalous Dirac point transport due to extended defects in bilayer graphene. Nat Commun 2017; 8:342. [PMID: 28839136 PMCID: PMC5571127 DOI: 10.1038/s41467-017-00397-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 06/27/2017] [Indexed: 11/21/2022] Open
Abstract
Charge transport at the Dirac point in bilayer graphene exhibits two dramatically different transport states, insulating and metallic, that occur in apparently otherwise indistinguishable experimental samples. We demonstrate that the existence of these two transport states has its origin in an interplay between evanescent modes, that dominate charge transport near the Dirac point, and disordered configurations of extended defects in the form of partial dislocations. In a large ensemble of bilayer systems with randomly positioned partial dislocations, the distribution of conductivities is found to be strongly peaked at both the insulating and metallic limits. We argue that this distribution form, that occurs only at the Dirac point, lies at the heart of the observation of both metallic and insulating states in bilayer graphene. In seemingly indistinguishable bilayer graphene samples, two distinct transport regimes, insulating and metallic, have been identified experimentally. Here, the authors demonstrate that these two states originate from the interplay between extended defects and evanescent modes at the Dirac point.
Collapse
Affiliation(s)
- Sam Shallcross
- Lehrstuhl für Theoretische Festkörperphysik, Staudstr. 7-B2, 91058, Erlangen, Germany.
| | - Sangeeta Sharma
- Max-Planck-Institut für Mikrostrukturphysik Weinberg 2, D-06120, Halle, Germany
| | - Heiko B Weber
- Lehrstuhl für Angewandte Physik, Staudtstr. 7, 91058, Erlangen, Germany.,Interdisziplinäres Zentrum für Molekulare Materialien, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany
| |
Collapse
|
18
|
Jaskólski W, Pelc M, Chico L, Ayuela A. Existence of nontrivial topologically protected states at grain boundaries in bilayer graphene: signatures and electrical switching. NANOSCALE 2016; 8:6079-6084. [PMID: 26931739 DOI: 10.1039/c5nr08630b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Recent experiments [L. Ju, et al., Nature, 2015, 520, 650] confirm the existence of gapless states at domain walls created in gated bilayer graphene, when the sublattice stacking is changed from AB to BA. These states are significant because they are topologically protected, valley-polarized and give rise to conductance along the domain wall. Current theoretical models predict the appearance of such states only at domain walls, which preserve the sublattice order. Here we show that the appearance of the topologically protected states in stacking domain walls can be much more common in bilayer graphene, since they can also emerge in unexpected geometries, e.g., at grain boundaries with atomic-scale topological defects. We focus on a bilayer system in which one of the layers contains a line of octagon-double pentagon defects that mix graphene sublattices. We demonstrate that gap states are preserved even with pentagonal defects. Remarkably, unlike previous predictions, the number of gap states changes by inverting the gate polarization, yielding an asymmetric conductance along the grain boundary under gate reversal. This effect, linked to defect states, should be detectable in transport measurements and could be exploited in electrical switches.
Collapse
Affiliation(s)
- W Jaskólski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland
| | - M Pelc
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland and Centro de Fisica de Materiales, CFM-MPC CSIC-UPV/EHU, Donostia International Physics Center (DIPC) and Departamento de Fisica de Materiales, Facultad de Quimicas, UPV-EHU, 20018 San Sebastian, Spain
| | - Leonor Chico
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Consejo Superior de Investigaciones Científicas, C/ Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - A Ayuela
- Centro de Fisica de Materiales, CFM-MPC CSIC-UPV/EHU, Donostia International Physics Center (DIPC) and Departamento de Fisica de Materiales, Facultad de Quimicas, UPV-EHU, 20018 San Sebastian, Spain
| |
Collapse
|
19
|
Lebedev AV, Lebedeva IV, Knizhnik AA, Popov AM. Interlayer interaction and related properties of bilayer hexagonal boron nitride: ab initio study. RSC Adv 2016. [DOI: 10.1039/c5ra20882c] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Properties of hexagonal boron nitride bilayer related to interlayer interaction (width and formation energy of dislocations, shear mode frequency, etc.) are estimated by approximation of potential energy surface by first Fourier harmonics.
Collapse
Affiliation(s)
| | - Irina V. Lebedeva
- Nano-Bio Spectroscopy Group and ETSF Scientific Development Centre
- Departamento de Física de Materiales
- Universidad del País Vasco UPV/EHU
- San Sebastian E-20018
- Spain
| | - Andrey A. Knizhnik
- Kintech Lab Ltd
- Moscow 123182
- Russia
- National Research Centre “Kurchatov Institute”
- Moscow 123182
| | - Andrey M. Popov
- Institute for Spectroscopy of Russian Academy of Sciences
- Moscow 142190
- Russia
| |
Collapse
|
20
|
Lei Y, Jiang W, Dai X, Song R, Wang B, Gao Y, Wang Z. Slippage in stacking of graphene nanofragments induced by spin polarization. Sci Rep 2015; 5:10985. [PMID: 26078005 PMCID: PMC4468519 DOI: 10.1038/srep10985] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/12/2015] [Indexed: 01/22/2023] Open
Abstract
Spin polarization and stacking are interesting effects in complex molecular systems and are both presented in graphene-based materials. Their possible combination may provide a new perspective in understanding the intermolecular force. The nanoscale graphene structures with zigzag edges could possess spin-polarized ground states. However, the mechanical effect of spin polarization in stacking of graphene nanofragments is not clear. Here we demonstrate the displacement between two stacked rhombic graphene nanofragments induced by spin polarization, using first-principles density-functional methods. We found that, in stacking of two rhombic graphene nanofragments, a spin-polarized stacked conformation with zero total spin is energetically more favorable than the closed-shell stacking. The spin-polarized conformation gives a further horizontal interlayer displacement within 1 angstrom compared with the closed-shell structure. This result highlights that, besides the well-known phenomenologically interpreted van der Waals forces, a specific mechanism dependent on the monomeric spin polarization may lead to obvious mechanical effects in some intermolecular interactions.
Collapse
Affiliation(s)
- Yanyu Lei
- 1] Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, People's Republic of China [2] Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012, People's Republic of China
| | - Wanrun Jiang
- 1] Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, People's Republic of China [2] Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012, People's Republic of China
| | - Xing Dai
- 1] Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, People's Republic of China [2] Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012, People's Republic of China
| | - Ruixia Song
- 1] Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, People's Republic of China [2] Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012, People's Republic of China
| | - Bo Wang
- 1] Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, People's Republic of China [2] Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012, People's Republic of China
| | - Yang Gao
- 1] Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, People's Republic of China [2] Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012, People's Republic of China
| | - Zhigang Wang
- 1] Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, People's Republic of China [2] Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012, People's Republic of China
| |
Collapse
|
21
|
Yan K, Wei Z, Li J, Chen H, Yi Y, Zheng X, Long X, Wang Z, Wang J, Xu J, Yang S. High-performance graphene-based hole conductor-free perovskite solar cells: Schottky junction enhanced hole extraction and electron blocking. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:2269-2274. [PMID: 25641809 DOI: 10.1002/smll.201403348] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 12/08/2014] [Indexed: 06/04/2023]
Abstract
Multilayered graphene and single-layered graphene are assembled onto perovskite films in the form of Schottky junctions and ohmic contacts, respectively, for the production of a graphene-based hole transporting material-free perovskite solar cell. Multilayered graphene extracts charge selectively and efficiently, delivering a higher efficiency of 11.5% than single-layered graphene (6.7%).
Collapse
Affiliation(s)
- Keyou Yan
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- Department of Electronic Engineering, Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Zhanhua Wei
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jinkai Li
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Haining Chen
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Ya Yi
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xiaoli Zheng
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xia Long
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Zilong Wang
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jiannong Wang
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jianbin Xu
- Department of Electronic Engineering, Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Shihe Yang
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| |
Collapse
|
22
|
Koren E, Lortscher E, Rawlings C, Knoll AW, Duerig U. Adhesion and friction in mesoscopic graphite contacts. Science 2015; 348:679-83. [DOI: 10.1126/science.aaa4157] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
23
|
Insulating state in tetralayers reveals an even-odd interaction effect in multilayer graphene. Nat Commun 2015; 6:6419. [PMID: 25732058 PMCID: PMC4366515 DOI: 10.1038/ncomms7419] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/27/2015] [Indexed: 11/08/2022] Open
Abstract
Close to charge neutrality, the electronic properties of graphene and its multilayers are sensitive to electron-electron interactions. In bilayers, for instance, interactions are predicted to open a gap between valence and conduction bands, turning the system into an insulator. In mono and (Bernal-stacked) trilayers, which remain conducting at low temperature, interactions do not have equally drastic consequences. It is expected that interaction effects become weaker for thicker multilayers, whose behaviour should converge to that of graphite. Here we show that this expectation does not correspond to reality by revealing the occurrence of an insulating state close to charge neutrality in Bernal-stacked tetralayer graphene. The phenomenology-incompatible with the behaviour expected from the single-particle band structure-resembles that observed in bilayers, but the insulating state in tetralayers is visible at higher temperature. We explain our findings, and the systematic even-odd effect of interactions in Bernal-stacked layers of different thickness that emerges from experiments, in terms of a generalization of the interaction-driven, symmetry-broken states proposed for bilayers.
Collapse
|
24
|
Huang YK, Chen SC, Ho YH, Lin CY, Lin MF. Feature-rich magnetic quantization in sliding bilayer graphenes. Sci Rep 2014; 4:7509. [PMID: 25515085 PMCID: PMC4268647 DOI: 10.1038/srep07509] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/14/2014] [Indexed: 01/09/2023] Open
Abstract
The generalized tight-binding model, based on the subenvelope functions of distinct sublattices, is developed to investigate the magnetic quantization in sliding bilayer graphenes. The relative shift of two graphene layers induces a dramatic transformation between the Dirac-cone structure and the parabolic band structure, and thus leads to drastic changes of Landau levels (LLs) in the spatial symmetry, initial formation energy, intergroup anti-crossing, state degeneracy and semiconductor-metal transition. There exist three kinds of LLs, i.e., well-behaved, perturbed and undefined LLs, which are characterized by a specific mode, a main mode plus side modes, and a disordered mode, respectively. Such LLs are clearly revealed in diverse magneto-optical selection rules. Specially, the undefined LLs frequently exhibit intergroup anti-crossings in the field-dependent energy spectra, and show a large number of absorption peaks without optical selection rules.
Collapse
Affiliation(s)
- Yao-Kung Huang
- Department of Physics, National Cheng Kung University, Taiwan
| | - Szu-Chao Chen
- Department of Physics, National Cheng Kung University, Taiwan
| | - Yen-Hung Ho
- Department of Physics and Texas Center for Superconductivity, University of Houston, Texas, U.S.A
| | - Chiun-Yan Lin
- Department of Physics, National Cheng Kung University, Taiwan
| | - Ming-Fa Lin
- 1] Department of Physics, National Cheng Kung University, Taiwan [2] National Center for Theoretical Sciences (south), Taiwan
| |
Collapse
|