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Shilov AL, Kashchenko MA, Pantaleón Peralta PA, Wang Y, Kravtsov M, Kudriashov A, Zhan Z, Taniguchi T, Watanabe K, Slizovskiy S, Novoselov KS, Fal'ko VI, Guinea F, Bandurin DA. High-Mobility Compensated Semimetals, Orbital Magnetization, and Umklapp Scattering in Bilayer Graphene Moiré Superlattices. ACS Nano 2024; 18:11769-11777. [PMID: 38648369 DOI: 10.1021/acsnano.3c13212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Twist-controlled moiré superlattices (MSs) have emerged as a versatile platform for realizing artificial systems with complex electronic spectra. The combination of Bernal-stacked bilayer graphene (BLG) and hexagonal boron nitride (hBN) can give rise to an interesting MS, which has recently featured a set of unexpected behaviors, such as unconventional ferroelectricity and the electronic ratchet effect. Yet, the understanding of the electronic properties of BLG/hBN MS has, at present, remained fairly limited. Here, we combine magneto-transport and low-energy sub-THz excitation to gain insights into the properties of this MS. We demonstrate that the alignment between BLG and hBN crystal lattices results in the emergence of compensated semimetals at some integer fillings of the moiré bands, separated by van Hove singularities where the Lifshitz transition occurs. A particularly pronounced semimetal develops when eight holes reside in the moiré unit cell, where coexisting high-mobility electron and hole systems feature strong magnetoresistance reaching 2350% already at B = 0.25 T. Next, by measuring the THz-driven Nernst effect in remote bands, we observe valley splitting, indicating an orbital magnetization characterized by a strongly enhanced effective gv-factor of 340. Finally, using THz photoresistance measurements, we show that the high-temperature conductivity of the BLG/hBN MS is limited by electron-electron umklapp processes. Our multifaceted analysis introduces THz-driven magnetotransport as a convenient tool to probe the band structure and interaction effects in van der Waals materials and provides a comprehensive understanding of the BLG/hBN MS.
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Affiliation(s)
- Artur L Shilov
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Mikhail A Kashchenko
- Programmable Functional Materials Lab, Center for Neurophysics and Neuromorphic Technologies, Moscow 127495, Russia
| | | | - Yibo Wang
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore 117575, Singapore
| | - Mikhail Kravtsov
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore 117575, Singapore
| | - Andrei Kudriashov
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore 117575, Singapore
| | - Zhen Zhan
- IMDEA Nanoscience, Faraday 9, Madrid 28015, Spain
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute of Material Science, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute of Material Science, Tsukuba 305-0044, Japan
| | - Sergey Slizovskiy
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, U.K
| | - Kostya S Novoselov
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore 117575, Singapore
| | - Vladimir I Fal'ko
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, U.K
| | - Francisco Guinea
- IMDEA Nanoscience, Faraday 9, Madrid 28015, Spain
- Donostia International Physics Center, Paseo Manuel de Lardizábal 4, San Sebastián 20018, Spain
| | - Denis A Bandurin
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore
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Mohanty S, Deb P. Sign-flipping intrinsic anomalous Hall conductivity with Berry curvature tunability in a half-metallic ferromagnet NbSe 2-VSe 2 lateral heterostructure. Nanoscale 2024. [PMID: 38618922 DOI: 10.1039/d3nr06266j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Single-layer half-metal magnets offer exciting scope in spin electronic quantum applications owing to improved spin transport, reduced interfacial resistance and streamlined device fabrication. Herein, we report the emergence of sign-flipping intrinsic anomalous Hall conductivity (AHC) as a result of changes in Berry curvature under an external electric field and half metallicity in a lateral heterostructure composed of centrosymmetric metallic monolayers 1T-NbSe2 and 1T-VSe2. The metallic monolayers 1T-NbSe2 and 1T-VSe2 laterally interfaced along the zigzag orientation break inversion symmetry at the interface and result in distinctive Berry curvature features. Furthermore, the half-metallic character was prominent with gapped states in the spin-up channel, while the spin-down state remained conductive; we observed the unique manifestation of sign-flipping intrinsic AHC at the Fermi level in addition to the electron- and hole-doped regions. This sign-flipping aspect of AHC at the Fermi level is of fundamental importance from the prospect of real-time device applications as it eliminates the necessity of supplementary actions, such as doping and strain engineering, which are traditionally employed to achieve AHC sign reversal. Additionally, a phase transition from half metal to metal occurs at a field of 0.5 V Å-1 and beyond. Half metallicity with sign switching AHC via external electric field makes the lateral NbSe2-VSe2 heterostructure a potential candidate for real-time energy-efficient low-power spintronic devices.
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Affiliation(s)
- Saransha Mohanty
- Advanced Functional Materials Laboratory, Department of Physics, Tezpur University (Central University), Tezpur 784028, India.
| | - Pritam Deb
- Advanced Functional Materials Laboratory, Department of Physics, Tezpur University (Central University), Tezpur 784028, India.
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Maity K, Dayen JF, Doudin B, Gumeniuk R, Kundys B. Graphene Magnetoresistance Control by Photoferroelectric Substrate. ACS Nano 2024. [PMID: 38284570 DOI: 10.1021/acsnano.3c07277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
Ultralow dimensionality of 2D layers magnifies their sensitivity to adjacent charges enabling even postprocessing electric control of multifunctional structures. However, functionalizing 2D layers remains an important challenge for on-demand device-property exploitation. Here we report that an electrical and even fully optical way to control and write modifications to the magnetoresistive response of CVD-deposited graphene is achievable through the electrostatics of the photoferroelectric substrate. For electrical control, the ferroelectric polarization switch modifies graphene magnetoresistance by 67% due to a Fermi level shift with related modification in charge mobility. A similar function is also attained entirely by bandgap light due to the substrate photovoltaic effect. Moreover, an all-optical way to imprint and recover graphene magnetoresistance by light is reported as well as magnetic control of graphene transconductance. These findings extend photoferroelectric control in 2D structures to magnetic dimensions and advance wireless operation for sensors and field-effect transistors.
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Affiliation(s)
- Krishna Maity
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 23 rue du Loess, Strasbourg F-67000, France
| | - Jean-François Dayen
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 23 rue du Loess, Strasbourg F-67000, France
| | - Bernard Doudin
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 23 rue du Loess, Strasbourg F-67000, France
| | - Roman Gumeniuk
- Institut für Experimentelle Physik, TU Bergakademie Freiberg, Leipziger Str. 23, Freiberg 09596, Germany
| | - Bohdan Kundys
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 23 rue du Loess, Strasbourg F-67000, France
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Rocchino L, Balduini F, Schmid H, Molinari A, Luisier M, Süß V, Felser C, Gotsmann B, Zota CB. Magnetoresistive-coupled transistor using the Weyl semimetal NbP. Nat Commun 2024; 15:710. [PMID: 38267457 DOI: 10.1038/s41467-024-44961-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 01/04/2024] [Indexed: 01/26/2024] Open
Abstract
Semiconductor transistors operate by modulating the charge carrier concentration of a channel material through an electric field coupled by a capacitor. This mechanism is constrained by the fundamental transport physics and material properties of such devices-attenuation of the electric field, and limited mobility and charge carrier density in semiconductor channels. In this work, we demonstrate a new type of transistor that operates through a different mechanism. The channel material is a Weyl semimetal, NbP, whose resistivity is modulated via a magnetic field generated by an integrated superconductor. Due to the exceptionally large electron mobility of this material, which reaches over 1,000,000 cm2/Vs, and the strong magnetoresistive coupling, the transistor can generate significant transconductance amplification at nanowatt levels of power. This type of device can enable new low-power amplifiers, suitable for qubit readout operation in quantum computers.
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Affiliation(s)
- Lorenzo Rocchino
- IBM Research Europe-Zürich, Saümerstrasse 4, 8803, Rüschlikon, Switzerland.
| | - Federico Balduini
- IBM Research Europe-Zürich, Saümerstrasse 4, 8803, Rüschlikon, Switzerland
| | - Heinz Schmid
- IBM Research Europe-Zürich, Saümerstrasse 4, 8803, Rüschlikon, Switzerland
| | - Alan Molinari
- IBM Research Europe-Zürich, Saümerstrasse 4, 8803, Rüschlikon, Switzerland
| | | | - Vicky Süß
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - Bernd Gotsmann
- IBM Research Europe-Zürich, Saümerstrasse 4, 8803, Rüschlikon, Switzerland
| | - Cezar B Zota
- IBM Research Europe-Zürich, Saümerstrasse 4, 8803, Rüschlikon, Switzerland
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Dapolito M, Tsuneto M, Zheng W, Wehmeier L, Xu S, Chen X, Sun J, Du Z, Shao Y, Jing R, Zhang S, Bercher A, Dong Y, Halbertal D, Ravindran V, Zhou Z, Petrovic M, Gozar A, Carr GL, Li Q, Kuzmenko AB, Fogler MM, Basov DN, Du X, Liu M. Infrared nano-imaging of Dirac magnetoexcitons in graphene. Nat Nanotechnol 2023; 18:1409-1415. [PMID: 37605044 DOI: 10.1038/s41565-023-01488-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 07/17/2023] [Indexed: 08/23/2023]
Abstract
Magnetic fields can have profound effects on the motion of electrons in quantum materials. Two-dimensional electron systems subject to strong magnetic fields are expected to exhibit quantized Hall conductivity, chiral edge currents and distinctive collective modes referred to as magnetoplasmons and magnetoexcitons. Generating these propagating collective modes in charge-neutral samples and imaging them at their native nanometre length scales have thus far been experimentally elusive. Here we visualize propagating magnetoexciton polaritons at their native length scales and report their magnetic-field-tunable dispersion in near-charge-neutral graphene. Imaging these collective modes and their associated nano-electro-optical responses allows us to identify polariton-modulated optical and photo-thermal electric effects at the sample edges, which are the most pronounced near charge neutrality. Our work is enabled by innovations in cryogenic near-field optical microscopy techniques that allow for the nano-imaging of the near-field responses of two-dimensional materials under magnetic fields up to 7 T. This nano-magneto-optics approach allows us to explore and manipulate magnetopolaritons in specimens with low carrier doping via harnessing high magnetic fields.
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Affiliation(s)
- Michael Dapolito
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, Columbia University, New York, NY, USA
| | - Makoto Tsuneto
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Wenjun Zheng
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Lukas Wehmeier
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - Suheng Xu
- Department of Physics, Columbia University, New York, NY, USA
| | - Xinzhong Chen
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, Columbia University, New York, NY, USA
| | - Jiacheng Sun
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Zengyi Du
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Yinming Shao
- Department of Physics, Columbia University, New York, NY, USA
| | - Ran Jing
- Department of Physics, Columbia University, New York, NY, USA
| | - Shuai Zhang
- Department of Physics, Columbia University, New York, NY, USA
| | - Adrien Bercher
- Département de Physique de la Matière Quantique, Université de Genève, Genève 4, Switzerland
| | - Yinan Dong
- Department of Physics, Columbia University, New York, NY, USA
| | - Dorri Halbertal
- Department of Physics, Columbia University, New York, NY, USA
| | - Vibhu Ravindran
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Zijian Zhou
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Mila Petrovic
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Adrian Gozar
- Department of Physics, Yale University, New Haven, CT, USA
- Energy Sciences Institute, Yale University, West Haven, CT, USA
| | - G L Carr
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - Qiang Li
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Alexey B Kuzmenko
- Département de Physique de la Matière Quantique, Université de Genève, Genève 4, Switzerland
| | - Michael M Fogler
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - D N Basov
- Department of Physics, Columbia University, New York, NY, USA.
| | - Xu Du
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA.
| | - Mengkun Liu
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA.
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA.
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6
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Wang S, Wang L, Zhao Q, Wang X. Massive laser pulling of graphene nanosheets in water. Opt Express 2023; 31:34057-34063. [PMID: 37859170 DOI: 10.1364/oe.500995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/05/2023] [Indexed: 10/21/2023]
Abstract
Light manipulation of graphene-based materials attracts much attentions. As a new light manipulation concept, optical pulling develops rapidly in the past decade. However, optical pulling of graphene in liquid is rarely reported. In this work, laser pulling of graphene nanosheets (GN) in pure water by using common gauss beams is presented. This phenomenon holds for multiple incident laser wavelengths including 405 nm, 488 nm, 532 nm and 650 nm. A particle image velocimetry software PIVlab is adopted to analyze the velocity field information of GN. The laser pulling velocity of the GN is approximately ∼ 0.5 mm/s corresponding to ∼ 103 body length/s, which increases with an increase of the incident laser energy. This work presents a contactless mothed to massively pull microscale graphene materials in simple liquid, which supplies a potential manipulation technique for micro-nanofluidic devices and also provides a platform to investigate laser-graphene interaction in a simple liquid phase medium.
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