LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 15

Search options

  1. Article ; Online: Pseudo-Hydrodynamic Flow of Quasiparticles in Semimetal WTe

    Choi, Young-Gwan / Doan, Manh-Ha / Ngoc, Luu Ly Pham / Lee, Junsu / Choi, Gyung-Min / Chernodub, Maxim Nikolaevich

    Small (Weinheim an der Bergstrasse, Germany)

    2023  Volume 19, Issue 27, Page(s) e2206604

    Abstract: Recently, much interest has emerged in fluid-like electric charge transport in various solid-state systems. The hydrodynamic behavior of the electronic fluid reveals itself as a decrease of the electrical resistance with increasing temperature (the ... ...

    Abstract Recently, much interest has emerged in fluid-like electric charge transport in various solid-state systems. The hydrodynamic behavior of the electronic fluid reveals itself as a decrease of the electrical resistance with increasing temperature (the Gurzhi effect) in narrow channels, polynomial scaling of the resistance as a function of the channel width, violation of the Wiedemann-Franz law supported by the emergence of the Poiseuille flow. Similar to whirlpools in flowing water, the viscous electronic flow generates vortices, resulting in abnormal sign-changing electrical response driven by backflow. However, the question of whether the long-ranged sign-changing electrical response can be produced by a mechanism other than hydrodynamics has not been addressed so far. Here polarization-sensitive laser microscopy is used to demonstrate the emergence of visually similar abnormal sign-alternating patterns in semi-metallic tungsten ditelluride at room temperature where this material does not exhibit true hydrodynamics. It is found that the neutral quasiparticle current consisting of electrons and holes obeys an equation remarkably similar to the Navier-Stokes equation. In particular, the momentum relaxation is replaced by the much slower process of quasiparticle recombination. This pseudo-hydrodynamic flow of quasiparticles leads to a sign-changing charge accumulation pattern via different diffusivities of electrons and holes.
    Language English
    Publishing date 2023-03-23
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 2168935-0
    ISSN 1613-6829 ; 1613-6810
    ISSN (online) 1613-6829
    ISSN 1613-6810
    DOI 10.1002/smll.202206604
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  2. Book ; Online: Pseudo-hydrodynamic flow of quasiparticles in semimetal WTe2 at room temperature

    Choi, Young-Gwan / Doan, Manh-Ha / Choi, Gyung-Min / Chernodub, Maxim N.

    2022  

    Abstract: Recently, much interest has emerged in fluid-like electric charge transport in various solid-state systems. The hydrodynamic behavior of the electronic fluid reveals itself as a decrease of the electrical resistance with increasing temperature (the ... ...

    Abstract Recently, much interest has emerged in fluid-like electric charge transport in various solid-state systems. The hydrodynamic behavior of the electronic fluid reveals itself as a decrease of the electrical resistance with increasing temperature (the Gurzhi effect) in narrow conducting channels, polynomial scaling of the resistance as a function of the channel width, substantial violation of the Wiedemann-Franz law supported by the emergence of the Poiseuille flow. Similarly to whirlpools in flowing water, the viscous electronic flow generates vortices, resulting in abnormal sign-changing electrical response driven by the backflow of electrical current. Experimentally, the presence of the hydrodynamic vortices was observed in low-temperature graphene as a negative voltage drop near the current-injecting contacts. However, the question of whether the long-ranged sign-changing electrical response can be produced by a mechanism other than hydrodynamics has not been addressed so far. Here we use polarization-sensitive laser microscopy to demonstrate the emergence of visually similar abnormal sign-alternating patterns in charge density in multilayer tungsten ditelluride at room temperature where this material does not exhibit true electronic hydrodynamics. We argue that this pseudo-hydrodynamic behavior appears due to a subtle interplay between the diffusive transport of electrons and holes. In particular, the sign-alternating charge accumulation in WTe2 is supported by the unexpected backflow of compressible neutral electron-hole current, which creates charge-neutral whirlpools in the bulk of this nearly compensated semimetal. We demonstrate that the exceptionally large spatial size of the charge domains is sustained by the long recombination time of electron-hole pairs.

    Comment: 14 pages, 3 figures + supplementary material
    Keywords Condensed Matter - Mesoscale and Nanoscale Physics ; Condensed Matter - Materials Science ; Physics - Fluid Dynamics
    Publishing date 2022-01-20
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  3. Book ; Online: Visualizing thickness-dependent magnetic textures in few-layer $\text{Cr}_2\text{Ge}_2\text{Te}_6$

    Vervelaki, Andriani / Bagani, Kousik / Jetter, Daniel / Doan, Manh-Ha / Chau, Tuan K. / Gross, Boris / Christensen, Dennis / Bøggild, Peter / Poggio, Martino

    2023  

    Abstract: Magnetic ordering in two-dimensional (2D) materials has recently emerged as a promising platform for data storage, computing, and sensing. To advance these developments, it is vital to gain a detailed understanding of how the magnetic order evolves on ... ...

    Abstract Magnetic ordering in two-dimensional (2D) materials has recently emerged as a promising platform for data storage, computing, and sensing. To advance these developments, it is vital to gain a detailed understanding of how the magnetic order evolves on the nanometer-scale as a function of the number of atomic layers and applied magnetic field. Here, we image few-layer $\text{Cr}_2\text{Ge}_2\text{Te}_6$ using a combined scanning superconducting quantum interference device and atomic force microscopy probe. Maps of the material's stray magnetic field as a function of applied magnetic field reveal its magnetization per layer as well as the thickness-dependent magnetic texture. Using a micromagnetic model, we correlate measured stray-field patterns with the underlying magnetization configurations, including labyrinth domains and skyrmionic bubbles. Comparison between real-space images and simulations demonstrates that the layer dependence of the material's magnetic texture is a result of the thickness-dependent balance between crystalline and shape anisotropy. These findings represent an important step towards 2D spintronic devices with engineered spin configurations and controlled dependence on external magnetic fields.

    Comment: 15 pages, 4 figures, and supplementary information
    Keywords Condensed Matter - Mesoscale and Nanoscale Physics ; Condensed Matter - Materials Science
    Subject code 530
    Publishing date 2023-11-14
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  4. Article ; Online: Room-Temperature Mesoscopic Fluctuations and Coulomb Drag in Multilayer WSe

    Doan, Manh-Ha / Jin, Youngjo / Chau, Tuan Khanh / Joo, Min-Kyu / Lee, Young Hee

    Advanced materials (Deerfield Beach, Fla.)

    2019  Volume 31, Issue 17, Page(s) e1900154

    Abstract: Mesoscopic fluctuations, manifesting the quantum interference (QI) of electrons, have been theoretically proposed in bilayer Coulomb drag systems. Unfortunately, these phenomena are usually observed at cryogenic temperatures, which severely limits their ... ...

    Abstract Mesoscopic fluctuations, manifesting the quantum interference (QI) of electrons, have been theoretically proposed in bilayer Coulomb drag systems. Unfortunately, these phenomena are usually observed at cryogenic temperatures, which severely limits their novel physics for pragmatic applications. In this paper, observation of room-temperature QI and Coulomb drag in a multilayer WSe
    Language English
    Publishing date 2019-03-13
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 1474949-X
    ISSN 1521-4095 ; 0935-9648
    ISSN (online) 1521-4095
    ISSN 0935-9648
    DOI 10.1002/adma.201900154
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  5. Article: Super-Resolution Nanolithography of Two-Dimensional Materials by Anisotropic Etching

    Danielsen, Dorte R. / Lyksborg-Andersen, Anton / Nielsen, Kirstine E. S. / Jessen, Bjarke S. / Booth, Timothy J. / Doan, Manh-Ha / Zhou, Yingqiu / Bøggild, Peter / Gammelgaard, Lene

    ACS applied materials & interfaces. 2021 Aug. 25, v. 13, no. 35

    2021  

    Abstract: Nanostructuring allows altering of the electronic and photonic properties of two-dimensional (2D) materials. The efficiency, flexibility, and convenience of top-down lithography processes are, however, compromised by nanometer-scale edge roughness and ... ...

    Abstract Nanostructuring allows altering of the electronic and photonic properties of two-dimensional (2D) materials. The efficiency, flexibility, and convenience of top-down lithography processes are, however, compromised by nanometer-scale edge roughness and resolution variability issues, which especially affect the performance of 2D materials. Here, we study how dry anisotropic etching of multilayer 2D materials with sulfur hexafluoride (SF₆) may overcome some of these issues, showing results for hexagonal boron nitride (hBN), tungsten disulfide (WS₂), tungsten diselenide (WSe₂), molybdenum disulfide (MoS₂), and molybdenum ditelluride (MoTe₂). Scanning electron microscopy and transmission electron microscopy reveal that etching leads to anisotropic hexagonal features in the studied transition metal dichalcogenides, with the relative degree of anisotropy ranked as: WS₂ > WSe₂ > MoTe₂ ∼ MoS₂. Etched holes are terminated by zigzag edges while etched dots (protrusions) are terminated by armchair edges. This can be explained by Wulff constructions, taking the relative stabilities of the edges and the AA′ stacking order into account. Patterns in WS₂ are transferred to an underlying graphite layer, demonstrating a possible use for creating sub-10 nm features. In contrast, multilayer hBN exhibits no lateral anisotropy but shows consistent vertical etch angles, independent of crystal orientation. Using an hBN crystal as the base, ultrasharp corners can be created in lithographic patterns, which are then transferred to a graphite crystal underneath. We find that the anisotropic SF₆ reactive ion etching process makes it possible to downsize nanostructures and obtain smooth edges, sharp corners, and feature sizes significantly below the resolution limit of electron beam lithography. The nanostructured 2D materials can be used themselves or as etch masks to pattern other nanomaterials.
    Keywords anisotropy ; boron nitride ; graphene ; molybdenum ; molybdenum disulfide ; photons ; roughness ; sulfur hexafluoride ; transmission electron microscopy ; tungsten
    Language English
    Dates of publication 2021-0825
    Size p. 41886-41894.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1944-8252
    DOI 10.1021/acsami.1c09923
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  6. Article ; Online: Facile Doping in Two-Dimensional Transition-Metal Dichalcogenides by UV Light.

    Ly, Thuc Hue / Deng, Qingming / Doan, Manh Ha / Li, Lain-Jong / Zhao, Jiong

    ACS applied materials & interfaces

    2018  Volume 10, Issue 35, Page(s) 29893–29901

    Abstract: Two-dimensional (2D) materials have been emerging as potential candidates for the next-generation materials in various technology fields. The performance of the devices based on these 2D materials depends on their intrinsic band structures as well as the ...

    Abstract Two-dimensional (2D) materials have been emerging as potential candidates for the next-generation materials in various technology fields. The performance of the devices based on these 2D materials depends on their intrinsic band structures as well as the extrinsic (doping) effects such as surrounding chemicals and environmental oxygen/moisture, which strongly determines their Fermi energy level. Herein, we report the UV treatments on the 2D transition-metal dichalcogenides, to controllably dope the samples without damaging the crystal structures or quenching the luminescence properties. More surprisingly, both n-type and p-type doping can be achieved depending on the initial status of the sample and the UV treatment conditions. The doping mechanisms were elaborated on the atomic scale with transmission electron microscopy and ab initio calculations. The facile doping by UV light has potential to be integrated with photolithography processes, aiming for the large-scale integrated device/circuits design and fabrications.
    Language English
    Publishing date 2018-08-23
    Publishing country United States
    Document type Journal Article
    ISSN 1944-8252
    ISSN (online) 1944-8252
    DOI 10.1021/acsami.8b09797
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  7. Article ; Online: Minimizing Trap Charge Density towards an Ideal Diode in Graphene-Silicon Schottky Solar Cell.

    Adhikari, Subash / Biswas, Chandan / Doan, Manh-Ha / Kim, Sung-Tae / Kulshreshtha, Chandramouli / Lee, Young Hee

    ACS applied materials & interfaces

    2018  Volume 11, Issue 1, Page(s) 880–888

    Abstract: Photovoltaic device performance of graphene/n-Si Schottky diodes is largely affected by inhomogeneous oxide formation at the interface that suppresses the tunneling current of injected and photoexcited charges. The accumulated trap charges at low current ...

    Abstract Photovoltaic device performance of graphene/n-Si Schottky diodes is largely affected by inhomogeneous oxide formation at the interface that suppresses the tunneling current of injected and photoexcited charges. The accumulated trap charges at low current induce charge recombination at the interface and degrade the ideality factor of the diode and the fill factor (FF) of the solar cell. This consequently gives rise to a nonlinear current-voltage ( I- V) feature in solar cells, commonly known as an S-shaped kink, which can be engineered by optimizing the interface barrier thickness or by increasing the carrier mobility. Here, we present chemical and electrochemical doping methods to increase the conductivity of graphene that transforms nonlinear kink photodiodes with a low FF and solar cell efficiency towards trap-free linear photovoltaic I- V. Space-charge-limited-current manifested Ohmic I- V diode behavior with enhanced conductance in graphene by injecting homogeneous ionic liquid; confirming the significant reduction of trap charge density. This was further congruent with the disappearance of the nonlinear kink in photodiodes with a high FF and nearly ideal diodes. The solar cell efficiency obtained with our strategy is around 13.6% and suggests possibilities to reach the theoretical limit of 19% by tailoring parameters such as conductance of graphene, carrier density of Si, and oxidation of the interfaces.
    Language English
    Publishing date 2018-12-28
    Publishing country United States
    Document type Journal Article
    ISSN 1944-8252
    ISSN (online) 1944-8252
    DOI 10.1021/acsami.8b18140
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  8. Article ; Online: Super-Resolution Nanolithography of Two-Dimensional Materials by Anisotropic Etching.

    Danielsen, Dorte R / Lyksborg-Andersen, Anton / Nielsen, Kirstine E S / Jessen, Bjarke S / Booth, Timothy J / Doan, Manh-Ha / Zhou, Yingqiu / Bøggild, Peter / Gammelgaard, Lene

    ACS applied materials & interfaces

    2021  Volume 13, Issue 35, Page(s) 41886–41894

    Abstract: Nanostructuring allows altering of the electronic and photonic properties of two-dimensional (2D) materials. The efficiency, flexibility, and convenience of top-down lithography processes are, however, compromised by nanometer-scale edge roughness and ... ...

    Abstract Nanostructuring allows altering of the electronic and photonic properties of two-dimensional (2D) materials. The efficiency, flexibility, and convenience of top-down lithography processes are, however, compromised by nanometer-scale edge roughness and resolution variability issues, which especially affect the performance of 2D materials. Here, we study how dry anisotropic etching of multilayer 2D materials with sulfur hexafluoride (SF
    Language English
    Publishing date 2021-08-25
    Publishing country United States
    Document type Journal Article
    ISSN 1944-8252
    ISSN (online) 1944-8252
    DOI 10.1021/acsami.1c09923
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  9. Article ; Online: Ferromagnetic Order at Room Temperature in Monolayer WSe2 Semiconductor via Vanadium Dopant

    Seok Joon Yun / Dinh Loc Duong / Doan Manh Ha / Kirandeep Singh / Thanh Luan Phan / Wooseon Choi / Young‐Min Kim / Young Hee Lee

    Advanced Science, Vol 7, Iss 9, Pp n/a-n/a (2020)

    2020  

    Abstract: Abstract Diluted magnetic semiconductors including Mn‐doped GaAs are attractive for gate‐controlled spintronics but Curie transition at room temperature with long‐range ferromagnetic order is still debatable to date. Here, the room‐temperature ... ...

    Abstract Abstract Diluted magnetic semiconductors including Mn‐doped GaAs are attractive for gate‐controlled spintronics but Curie transition at room temperature with long‐range ferromagnetic order is still debatable to date. Here, the room‐temperature ferromagnetic domains with long‐range order in semiconducting V‐doped WSe2 monolayer synthesized by chemical vapor deposition are reported. Ferromagnetic order is manifested using magnetic force microscopy up to 360 K, while retaining high on/off current ratio of ≈105 at 0.1% V‐doping concentration. The V‐substitution to W sites keeps a V–V separation distance of 5 nm without V–V aggregation, scrutinized by high‐resolution scanning transmission electron microscopy. More importantly, the ferromagnetic order is clearly modulated by applying a back‐gate bias. The findings open new opportunities for using 2D transition metal dichalcogenides for future spintronics.
    Keywords gate‐controlled spintronics ; gate tunable magnetism ; magnetic domains ; magnetic semiconductors ; room temperature ferromagnetism ; vanadium‐doped tungsten diselenide ; Science ; Q
    Language English
    Publishing date 2020-05-01T00:00:00Z
    Publisher Wiley
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  10. Article ; Online: Two-Terminal Multibit Optical Memory via van der Waals Heterostructure.

    Tran, Minh Dao / Kim, Hyun / Kim, Jun Suk / Doan, Manh Ha / Chau, Tuan Khanh / Vu, Quoc An / Kim, Ji-Hee / Lee, Young Hee

    Advanced materials (Deerfield Beach, Fla.)

    2018  Volume 31, Issue 7, Page(s) e1807075

    Abstract: 2D van der Waals (vdWs) heterostructures exhibit intriguing optoelectronic properties in photodetectors, solar cells, and light-emitting diodes. In addition, these materials have the potential to be further extended to optical memories with promising ... ...

    Abstract 2D van der Waals (vdWs) heterostructures exhibit intriguing optoelectronic properties in photodetectors, solar cells, and light-emitting diodes. In addition, these materials have the potential to be further extended to optical memories with promising broadband applications for image sensing, logic gates, and synaptic devices for neuromorphic computing. In particular, high programming voltage, high off-power consumption, and circuital complexity in integration are primary concerns in the development of three-terminal optical memory devices. This study describes a multilevel nonvolatile optical memory device with a two-terminal floating-gate field-effect transistor with a MoS
    Language English
    Publishing date 2018-12-27
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 1474949-X
    ISSN 1521-4095 ; 0935-9648
    ISSN (online) 1521-4095
    ISSN 0935-9648
    DOI 10.1002/adma.201807075
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

To top