1
|
Yan Q, Wang S, Guan K, Guan X, He L. Cathodoluminescence and tip-plasmon resonance of Bi2Te3 triangular nanostructures. PLoS One 2024; 19:e0291251. [PMID: 38241382 PMCID: PMC10798455 DOI: 10.1371/journal.pone.0291251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/23/2023] [Indexed: 01/21/2024] Open
Abstract
Bi2Te3, as a topological insulator, is able to support plasmonic emission in the visible spectral range. Thin Bi2Te3 flakes can be exfoliated directly from a Bi2Te3 crystal, and the shape of Bi2Te3 flakes can be further modified by focused ion beam milling. Therefore, we have designed a Bi2Te3 triangular antenna with distinct tip angles for the application of plasmonic resonance. The plasmonic emission of the Bi2Te3 triangular antenna is excited and investigated by cathodoluminescence in the scanning electron microscope. Enhanced tip plasmons have been observed from distinct tips with angles of 20º, 36º, 54º, 70º, and 90º, respectively. Due to the confinement of geometric boundaries for oscillating charges, the resonant peak position of tip plasmon with a smaller angle has a blue shift. Moreover, the dependence of plasmonic behavior on the excitation position has been discovered as well. This research provides a unique approach to fabricate Bi2Te3 nanostructures and manipulate the corresponding plasmonic properties.
Collapse
Affiliation(s)
- Qigeng Yan
- Department of Physics, Baoding University, Baoding, Hebei, China
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, United States of America
| | - Siyuan Wang
- Department of Science and Research, Baoding University, Baoding, Hebei, China
| | - Kuiwen Guan
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, United States of America
| | - Xiaojin Guan
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, United States of America
| | - Lei He
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, United States of America
| |
Collapse
|
2
|
Bake A, Zhang Q, Ho CS, Causer GL, Zhao W, Yue Z, Nguyen A, Akhgar G, Karel J, Mitchell D, Pastuovic Z, Lewis R, Cole JH, Nancarrow M, Valanoor N, Wang X, Cortie D. Top-down patterning of topological surface and edge states using a focused ion beam. Nat Commun 2023; 14:1693. [PMID: 36973266 PMCID: PMC10042877 DOI: 10.1038/s41467-023-37102-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 02/27/2023] [Indexed: 03/29/2023] Open
Abstract
AbstractThe conducting boundary states of topological insulators appear at an interface where the characteristic invariant ℤ2 switches from 1 to 0. These states offer prospects for quantum electronics; however, a method is needed to spatially-control ℤ2 to pattern conducting channels. It is shown that modifying Sb2Te3 single-crystal surfaces with an ion beam switches the topological insulator into an amorphous state exhibiting negligible bulk and surface conductivity. This is attributed to a transition from ℤ2 = 1 → ℤ2 = 0 at a threshold disorder strength. This observation is supported by density functional theory and model Hamiltonian calculations. Here we show that this ion-beam treatment allows for inverse lithography to pattern arrays of topological surfaces, edges and corners which are the building blocks of topological electronics.
Collapse
|
3
|
Gracia-Abad R, Sangiao S, Kumar Chaluvadi S, Orgiani P, Teresa JMD. Ion-Induced Lateral Damage in the Focused Ion Beam Patterning of Topological Insulator Bi 2Se 3 Thin Films. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2244. [PMID: 36984129 PMCID: PMC10051711 DOI: 10.3390/ma16062244] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/03/2023] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Focused Ion Beam patterning has become a widely applied technique in the last few decades in the micro- and nanofabrication of quantum materials, representing an important advantage in terms of resolution and versatility. However, ion irradiation can trigger undesired effects on the target material, most of them related to the damage created by the impinging ions that can severely affect the crystallinity of the sample, compromising the application of Focused Ion Beam to the fabrication of micro- and nanosized systems. We focus here on the case of Bi2Se3, a topological material whose unique properties rely on its crystallinity. In order to study the effects of ion irradiation on the structure of Bi2Se3, we irradiated with Ga+ ions the full width of Hall-bar devices made from thin films of this material, with the purpose of inducing changes in the electrical resistance and characterizing the damage created during the process. The results indicate that a relatively high ion dose is necessary to introduce significant changes in the conduction. This ion dose creates medium-range lateral damage in the structure, manifested through the formation of an amorphous region that can extend laterally up to few hundreds of nanometers beyond the irradiated area. This amorphous material is no longer expected to behave as intrinsic Bi2Se3, indicating a spatial limitation for the devices fabricated through this technique.
Collapse
Affiliation(s)
- Rubén Gracia-Abad
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Soraya Sangiao
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | | | - Pasquale Orgiani
- CNR-IOM, TASC Laboratory in Area Science Park, 34149 Trieste, Italy
| | - José María De Teresa
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain
| |
Collapse
|
4
|
Hong Q, Zhang J, Wang S, Chu Z, Wang M, Sun J, Guo Q. Nanopatterning of silicon via the near-field enhancement effect upon double-pulse femtosecond laser exposure. APPLIED OPTICS 2021; 60:7790-7797. [PMID: 34613252 DOI: 10.1364/ao.433564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
Utilizing the near-field enhancement effect of a polystyrene microsphere, direct ablation of nanohole arrays by a temporal-shaping femtosecond (fs) laser pulse is presented. The nanohole arrays, which are circular, regular, and free of cracks, were processed without extra post-processing, and their average diameter decreased gradually, as the double-pulse delay increased until 2500 fs. The simulated results by a plasma model and finite difference time domain solution demonstrate that the size decrease of the structure is attributed to the increase of the ablation threshold of silicon. Through fs laser near-field fabrication, the FWHM of nanoholes can be reduced to approximately 50 nm (λ/16) and even to 23 nm when using the second harmonic laser at a wavelength of 400 nm.
Collapse
|
5
|
Bafekry A, Mortazavi B, Faraji M, Shahrokhi M, Shafique A, Jappor HR, Nguyen C, Ghergherehchi M, Feghhi SAH. Ab initio prediction of semiconductivity in a novel two-dimensional Sb 2X 3 (X= S, Se, Te) monolayers with orthorhombic structure. Sci Rep 2021; 11:10366. [PMID: 33990674 PMCID: PMC8121886 DOI: 10.1038/s41598-021-89944-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/28/2021] [Indexed: 02/04/2023] Open
Abstract
[Formula: see text] and [Formula: see text] are well-known layered bulk structures with weak van der Waals interactions. In this work we explore the atomic lattice, dynamical stability, electronic and optical properties of [Formula: see text], [Formula: see text] and [Formula: see text] monolayers using the density functional theory simulations. Molecular dynamics and phonon dispersion results show the desirable thermal and dynamical stability of studied nanosheets. On the basis of HSE06 and PBE/GGA functionals, we show that all the considered novel monolayers are semiconductors. Using the HSE06 functional the electronic bandgap of [Formula: see text], [Formula: see text] and [Formula: see text] monolayers are predicted to be 2.15, 1.35 and 1.37 eV, respectively. Optical simulations show that the first absorption coefficient peak for [Formula: see text], [Formula: see text] and [Formula: see text] monolayers along in-plane polarization is suitable for the absorption of the visible and IR range of light. Interestingly, optically anisotropic character along planar directions can be desirable for polarization-sensitive photodetectors. Furthermore, we systematically investigate the electrical transport properties with combined first-principles and Boltzmann transport theory calculations. At optimal doping concentration, we found the considerable larger power factor values of 2.69, 4.91, and 5.45 for hole-doped [Formula: see text], [Formula: see text], and [Formula: see text], respectively. This study highlights the bright prospect for the application of [Formula: see text], [Formula: see text] and [Formula: see text] nanosheets in novel electronic, optical and energy conversion systems.
Collapse
Affiliation(s)
- A Bafekry
- Department of Radiation Application, Shahid Beheshti University, Tehran, Iran.
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium.
| | - B Mortazavi
- Chair of Computational Science and Simulation Technology, Institute of Photonics, Department of Mathematics and Physics, Leibniz University of Hannover, Appelstrae 11, 30157, Hannover, Germany
| | - M Faraji
- Micro and Nanotechnology Graduate Program, TOBB University of Economics and Technology, Sogutozu Caddesi No 43 Sogutozu, 06560, Ankara, Turkey
| | - M Shahrokhi
- Department of Physics, Faculty of Science, University of Kurdistan, Sanandaj, 66177-15175, Iran
| | - A Shafique
- Department of Physics, Lahore University of Management Sciences, Lahore, Pakistan
| | - H R Jappor
- Department of Physics, College of Education for Pure Sciences, University of Babylon, Hilla, Iraq
| | - C Nguyen
- Department of Materials Science and Engineering, Le Quy Don Technical University, Ha Noi, 100000, Vietnam
| | - M Ghergherehchi
- Department of Electrical and Computer Engineering, Sungkyunkwan University, 16419, Suwon, Korea.
| | - S A H Feghhi
- Department of Radiation Application, Shahid Beheshti University, Tehran, Iran
| |
Collapse
|
6
|
Yadav R, Bhattacharyya B, Pandey A, Kaur M, Aloysius RP, Gupta A, Husale S. Accessing topological surface states and negative MR in sculpted nanowires of Bi 2Te 3 at ultra-low temperature. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:085301. [PMID: 33171442 DOI: 10.1088/1361-648x/abc944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Milling of 2D flakes is a simple method to fabricate nanomaterial of any desired shape and size. Inherently milling process can introduce the impurity or disorder which might show exotic quantum transport phenomenon when studied at the low temperature. Here we report temperature dependent weak antilocalization (WAL) effects in the sculpted nanowires of topological insulator in the presence of perpendicular magnetic field. The quadratic and linear magnetoconductivity (MC) curves at low temperature (>2 K) indicate the bulk contribution in the transport. A cusp feature in magnetoconductivity curves (positive magnetoresistance) at ultra low (<1 K) temperature and at magnetic field (<1 T) represent the WAL indicating the transport through surface states. The MC curves are discussed by using the 2D Hikami-Larkin-Nagaoka theory. The cross-over/interplay nature of positive and negative magnetoresistance observed in the MR curve at ultra-low temperature. Our results indicate that transport through topological surface states (TSS) in sculpted nanowires of Bi2Te3 can be achieved at mK range and linear MR observed at ∼2 K could be the coexistence of electron transport through TSS and contribution from the bulk band.
Collapse
Affiliation(s)
- Reena Yadav
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
- National Physical Laboratory, Council of Scientific and Industrial Research, Dr. K S Krishnan Road, New Delhi-110012, India
| | - Biplab Bhattacharyya
- National Physical Laboratory, Council of Scientific and Industrial Research, Dr. K S Krishnan Road, New Delhi-110012, India
| | - Animesh Pandey
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
- National Physical Laboratory, Council of Scientific and Industrial Research, Dr. K S Krishnan Road, New Delhi-110012, India
| | - Mandeep Kaur
- National Physical Laboratory, Council of Scientific and Industrial Research, Dr. K S Krishnan Road, New Delhi-110012, India
| | - R P Aloysius
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
- National Physical Laboratory, Council of Scientific and Industrial Research, Dr. K S Krishnan Road, New Delhi-110012, India
| | - Anurag Gupta
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
- National Physical Laboratory, Council of Scientific and Industrial Research, Dr. K S Krishnan Road, New Delhi-110012, India
| | - Sudhir Husale
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
- National Physical Laboratory, Council of Scientific and Industrial Research, Dr. K S Krishnan Road, New Delhi-110012, India
| |
Collapse
|
7
|
Gold Nanoisland Agglomeration upon the Substrate Assisted Chemical Etching Based on Thermal Annealing Process. CRYSTALS 2020. [DOI: 10.3390/cryst10060533] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In this study, we proposed the self-organization process and its localized surface plasmon resonance property (LSPR) to study the effect of chemically treated quartz glass substrates for gold nanoisland array formation. Firstly, we etched a quartz glass substrate using a sputter etching machine. Secondly, n-butanol was treated on the surface of the substrate. Then, we deposited a gold thin film on the substrate with assisted chemical etching. Finally, the self-organization method examined the thermal annealing of gold nanoisland arrays on a substrate. The results showed that the gold nanoisland that was aggregated on an etched quartz glass substrate was large and sparse, while the gold nanoisland aggregated on a chemically treated substrate was small and dense. Further, it was revealed that a substrate’s surface energy reduced chemical treating and increased the gold nanoisland contact angle on the substrate via the thermal annealing process. It was also confirmed that chemical treatment was useful to control the morphology of gold nanoisland arrays on a substrate, particularly when related to tuning their optical property.
Collapse
|
8
|
Yan Q, Li X, Liang B. Plasmonic Emission of Bullseye Nanoemitters on Bi 2Te 3 Nanoflakes. MATERIALS (BASEL, SWITZERLAND) 2020; 13:ma13071531. [PMID: 32225070 PMCID: PMC7178145 DOI: 10.3390/ma13071531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/17/2020] [Accepted: 03/24/2020] [Indexed: 06/10/2023]
Abstract
Topological insulators, such as Bi2Te3, have been confirmed to exhibit plasmon radiation over the entire visible spectral range. Herein, we fabricate bullseye nanoemitters, consisting of a central disk and concentric gratings, on the Bi2Te3 nanoflake. Due to the existence of edge plasmon modes, Bi2Te3 bullseye nanostructures are possible to converge light towards the central disk. Taking advantage of the excellent spatial resolution of cathodoluminescence (CL) characterization, it has been observed that plasmonic behaviors depend on the excitation location. A stronger plasmonic intensity and a wider CL spectral linewidth can be obtained at the edge of the central disk. In order to further improve the focusing ability, a cylindrical Pt nanostructure has been deposited on the central disk. Additionally, the finite element simulation indicates that the electric-field enhancement originates from the coupling process between the plasmonic emission from the Bi2Te3 bullseye and the Pt nanostructure. Finally, we find that enhancement efficiency depends on the thickness of the Pt nanostructure.
Collapse
|
9
|
Comparison between Focused Electron/Ion Beam-Induced Deposition at Room Temperature and under Cryogenic Conditions. MICROMACHINES 2019; 10:mi10120799. [PMID: 31766480 PMCID: PMC6952801 DOI: 10.3390/mi10120799] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/14/2019] [Accepted: 11/18/2019] [Indexed: 11/17/2022]
Abstract
In this contribution, we compare the performance of Focused Electron Beam-induced Deposition (FEBID) and Focused Ion Beam-induced Deposition (FIBID) at room temperature and under cryogenic conditions (the prefix “Cryo” is used here for cryogenic). Under cryogenic conditions, the precursor material condensates on the substrate, forming a layer that is several nm thick. Its subsequent exposure to a focused electron or ion beam and posterior heating to 50 °C reveals the deposit. Due to the extremely low charge dose required, Cryo-FEBID and Cryo-FIBID are found to excel in terms of growth rate, which is typically a few hundred/thousand times higher than room-temperature deposition. Cryo-FIBID using the W(CO)6 precursor has demonstrated the growth of metallic deposits, with resistivity not far from the corresponding deposits grown at room temperature. This paves the way for its application in circuit edit and the fast and direct growth of micro/nano-electrical contacts with decreased ion damage. The last part of the contribution is dedicated to the comparison of these techniques with other charge-based lithography techniques in terms of the charge dose required and process complexity. The comparison indicates that Cryo-FIBID is very competitive and shows great potential for future lithography developments.
Collapse
|
10
|
Metallic edge states in zig-zag vertically-oriented MoS 2 nanowalls. Sci Rep 2019; 9:15602. [PMID: 31666574 PMCID: PMC6821918 DOI: 10.1038/s41598-019-52119-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 10/11/2019] [Indexed: 11/09/2022] Open
Abstract
The remarkable properties of layered materials such as MoS2 strongly depend on their dimensionality. Beyond manipulating their dimensions, it has been predicted that the electronic properties of MoS2 can also be tailored by carefully selecting the type of edge sites exposed. However, achieving full control over the type of exposed edge sites while simultaneously modifying the dimensionality of the nanostructures is highly challenging. Here we adopt a top-down approach based on focus ion beam in order to selectively pattern the exposed edge sites. This strategy allows us to select either the armchair (AC) or the zig-zag (ZZ) edges in the MoS2 nanostructures, as confirmed by high-resolution transmission electron microscopy measurements. The edge-type dependence of the local electronic properties in these MoS2 nanostructures is studied by means of electron energy-loss spectroscopy measurements. This way, we demonstrate that the ZZ-MoS2 nanostructures exhibit clear fingerprints of their predicted metallic character. Our results pave the way towards novel approaches for the design and fabrication of more complex nanostructures based on MoS2 and related layered materials for applications in fields such as electronics, optoelectronics, photovoltaics, and photocatalysts.
Collapse
|
11
|
Lin TY, Lee SK, Huang GM, Huang CW, Tai KL, Huang CY, Lo YC, Wu WW. Electron Beam Irradiation-Induced Deoxidation and Atomic Flattening on the Copper Surface. ACS APPLIED MATERIALS & INTERFACES 2019; 11:40909-40915. [PMID: 31573187 DOI: 10.1021/acsami.9b14529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electron beam (e-beam) has been developed for nanomaterial observation and moreover to induce structural evolutions in atomic scale. In this work, we demonstrate the deoxidation of cuprous oxide (Cu2O) and the formation of an atomically flat surface on a Cu nanowire by e-beam irradiation. To develop e-beam irradiation applications, the relation between e-beam radiation and the atomic surface is significant. Through the density functional theory simulation of atomic sputtering, an obvious disparity in the sputtering threshold has been found under different structural conditions, which leads to different structural evolutions. Both surface deoxidation and atomic surface flattening reactions have been identified as self-limiting and irreversible processes via in situ transmission electron microscope observation. Under e-beam irradiation, the dynamic mechanism of atomic surface flattening is driven by the convergence of total surface energy and confirmed by climbing-image nudged elastic band (ci-NEB) calculations. With precise control, e-beam irradiation reveals enormous potentials in atomic surface engineering.
Collapse
Affiliation(s)
- Ting-Yi Lin
- Department of Materials Science and Engineering , National Chiao Tung University , 1001 University Road , Hsinchu 30010 , Taiwan
| | - Shih-Kuang Lee
- Department of Materials Science and Engineering , National Chiao Tung University , 1001 University Road , Hsinchu 30010 , Taiwan
| | - Guan-Min Huang
- Department of Materials Science and Engineering , National Chiao Tung University , 1001 University Road , Hsinchu 30010 , Taiwan
| | - Chun-Wei Huang
- Material and Chemical Research Laboratories, Nanotechnology Research Center , Industrial Technology Research Institute , 195, Sec. 4, Chung Hsing Road , Chutung, Hsinchu 31040 , Taiwan
| | - Kuo-Lun Tai
- Department of Materials Science and Engineering , National Chiao Tung University , 1001 University Road , Hsinchu 30010 , Taiwan
| | - Chih-Yang Huang
- Department of Materials Science and Engineering , National Chiao Tung University , 1001 University Road , Hsinchu 30010 , Taiwan
| | - Yu-Chieh Lo
- Department of Materials Science and Engineering , National Chiao Tung University , 1001 University Road , Hsinchu 30010 , Taiwan
| | - Wen-Wei Wu
- Department of Materials Science and Engineering , National Chiao Tung University , 1001 University Road , Hsinchu 30010 , Taiwan
- Center for the Semiconductor Technology Research , National Chiao Tung University , Hsinchu 30010 , Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters , National Tsing Hua University , Hsinchu 30013 , Taiwan
| |
Collapse
|
12
|
Spin-dependent scattering induced negative magnetoresistance in topological insulator Bi 2Te 3 nanowires. Sci Rep 2019; 9:7836. [PMID: 31127174 PMCID: PMC6534536 DOI: 10.1038/s41598-019-44265-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 05/14/2019] [Indexed: 11/22/2022] Open
Abstract
Studies of negative magnetoresistance in novel materials have recently been in the forefront of spintronic research. Here, we report an experimental observation of the temperature dependent negative magnetoresistance in Bi2Te3 topological insulator (TI) nanowires at ultralow temperatures (20 mK). We find a crossover from negative to positive magnetoresistance while increasing temperature under longitudinal magnetic field. We observe a large negative magnetoresistance which reaches −22% at 8 T. The interplay between negative and positive magnetoresistance can be understood in terms of the competition between dephasing and spin-orbit scattering time scales. Based on the first-principles calculations within a density functional theory framework, we demonstrate that disorder (substitutional) by Ga+ ion milling process, which is used to fabricate nanowires, induces local magnetic moments in Bi2Te3 crystal that can lead to spin-dependent scattering of surface and bulk electrons. These experimental findings show a significant advance in the nanoscale spintronics applications based on longitudinal magnetoresistance in TIs. Our experimental results of large negative longitudinal magnetoresistance in 3D TIs further indicate that axial anomaly is a universal phenomenon in generic 3D metals.
Collapse
|
13
|
Friedensen SE, Parkin WM, Mlack JT, Drndić M. Transmission Electron Microscope Nanosculpting of Topological Insulator Bismuth Selenide. ACS NANO 2018; 12:6949-6955. [PMID: 29890079 DOI: 10.1021/acsnano.8b02377] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We present a process for sculpting Bi2Se3 nanoflakes into application-relevant geometries using a high-resolution transmission electron microscope. This process takes several minutes to sculpt small areas and can be used to cut the Bi2Se3 into wires and rings, to thin areas of the Bi2Se3, and to drill circular holes and lines. We determined that this method allows for sub 10 nm features and results in clean edges along the drilled regions. Using in situ high-resolution imaging, selected area diffraction, and atomic force microscopy, we found that this lithography process preserves the crystal structure of Bi2Se3. TEM sculpting is more precise and potentially results in cleaner edges than does ion-beam modification; therefore, the promise of this method for thermoelectric and topological devices calls for further study into the transport properties of such structures.
Collapse
Affiliation(s)
- Sarah E Friedensen
- Department of Physics and Astronomy , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - William M Parkin
- Department of Physics and Astronomy , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Jerome T Mlack
- Department of Physics and Astronomy , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Marija Drndić
- Department of Physics and Astronomy , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| |
Collapse
|
14
|
Mazumder K, Sharma A, Kumar Y, Bankar P, More MA, Devan R, Shirage PM. Enhancement of field electron emission in topological insulator Bi2Se3 by Ni doping. Phys Chem Chem Phys 2018; 20:18429-18435. [DOI: 10.1039/c8cp01982g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nanostructures of bismuth selenide (Bi2Se3), a 3D topological insulator material, and nickel (Ni) doped Bi2Se3 samples were prepared by a hydrothermal method to explore the field emission properties.
Collapse
Affiliation(s)
- Kushal Mazumder
- Discipline of Physics
- Indian Institute of Technology Indore
- Simrol Campus
- Indore-453 552
- India
| | - Alfa Sharma
- Discipline of Metallurgy Engineering and Materials Science
- Indian Institute of Technology Indore
- Simrol Campus
- Indore-453 552
- India
| | - Yogendra Kumar
- Discipline of Metallurgy Engineering and Materials Science
- Indian Institute of Technology Indore
- Simrol Campus
- Indore-453 552
- India
| | - Prashant Bankar
- Physical and Materials Chemistry Division
- CSIR-National Chemical Laboratory
- Pashan
- India
- Department of Physics
| | | | - Rupesh Devan
- Discipline of Metallurgy Engineering and Materials Science
- Indian Institute of Technology Indore
- Simrol Campus
- Indore-453 552
- India
| | - Parasharam M. Shirage
- Discipline of Physics
- Indian Institute of Technology Indore
- Simrol Campus
- Indore-453 552
- India
| |
Collapse
|