LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 35

Search options

  1. Article: Preliminary

    Wong, Chi Ho / Lortz, Rolf

    Materials (Basel, Switzerland)

    2023  Volume 16, Issue 13

    Abstract: Many theoretical models of iron-based superconductors (IBSC) have been proposed, but the superconducting transition temperature ( ...

    Abstract Many theoretical models of iron-based superconductors (IBSC) have been proposed, but the superconducting transition temperature (
    Language English
    Publishing date 2023-06-28
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma16134674
    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: Realization of A Superconducting FeTe/Bi$_2$Te$_3$ Heterostructure

    He, Zhihao / Ho, Tin Seng Manfred / Lortz, Rolf / Sou, Iam Keong

    2023  

    Abstract: Before this study, we observed an intriguing occurrence of two-dimensional (2D) superconductivity in two heterostructures, Bi$_2$Te$_3$/FeTe and Sb$_2$Te$_3$/FeTe, which consist of a topological insulator (TI) on top and FeTe on the bottom. The objective ...

    Abstract Before this study, we observed an intriguing occurrence of two-dimensional (2D) superconductivity in two heterostructures, Bi$_2$Te$_3$/FeTe and Sb$_2$Te$_3$/FeTe, which consist of a topological insulator (TI) on top and FeTe on the bottom. The objective of this study was to create an inverted version of the Bi$_2$Te$_3$/FeTe (BT-FT) heterostructure, called FeTe/Bi$_2$Te$_3$ (FT-BT). Through in-situ reflection high-energy electron diffraction (RHEED), high-resolution x-ray diffraction (HRXRD) profiling and cross-sectional scanning transmission electron microscopy (STEM) imaging studies, it was found that at a relatively high growth temperature, FeTe grown on Bi$_2$Te$_3$ led to the extraction of Te from the Bi$_2$Te$_3$ layer, resulting the formation of Bi$_4$Te$_3$ as the bottom layer. This is attributed to the more negative formation energy of FeTe compared to that of Bi$_2$Te$_3$. In addition, a nearly ideal heterostructure of FeTe/Bi$_2$Te$_3$ was successfully fabricated at a lower growth temperature of FeTe with certain Fe and Te cell temperatures. This heterostructure exhibits superconductivity at approximately 12K. These studies present a new approach to realizing the Bi$_4$Te$_3$ component of the Bi-Te system, which could potentially be used to generate other components within the Bi-Te system. The realization of the FeTe/Bi$_2$Te$_3$ inverted heterostructure creates a platform for configuring structures with multiple interfaces between Bi$_2$Te$_3$ and FeTe. This is expected to enhance superconductivity due to its more three-dimensional nature.

    Comment: 17 pages, 5 figures
    Keywords Condensed Matter - Superconductivity ; Condensed Matter - Materials Science
    Publishing date 2023-12-16
    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. Article ; Online: Evidence for isotropic s-wave superconductivity in high-entropy alloys.

    Leung, Casey K W / Zhang, Xiaofu / von Rohr, Fabian / Lortz, Rolf / Jäck, Berthold

    Scientific reports

    2022  Volume 12, Issue 1, Page(s) 12773

    Abstract: High-entropy alloys (HEA) form through the random arrangement of five or more chemical elements on a crystalline lattice. Despite the significant amount of resulting compositional disorder, a subset of HEAs enters a superconducting state below critical ... ...

    Abstract High-entropy alloys (HEA) form through the random arrangement of five or more chemical elements on a crystalline lattice. Despite the significant amount of resulting compositional disorder, a subset of HEAs enters a superconducting state below critical temperatures, [Formula: see text] K. The superconducting properties of the known HEAs seem to suffice a Bardeen-Cooper-Schrieffer (BCS) description, but little is known about their superconducting order parameter and the microscopic role of disorder. We report on magnetic susceptibility measurements on films of the superconducting HEA (TaNb)[Formula: see text](ZrHfTi)[Formula: see text] for characterizing the lower and upper critical fields [Formula: see text] and [Formula: see text], respectively as a function of temperature T. Our resulting analysis of the Ginzburg-Landau coherence length and penetration depth demonstrates that HEAs of this type are single-band isotropic s-wave superconductors in the dirty limit. Despite a significant difference in the elemental composition between the [Formula: see text] and [Formula: see text] films, we find that the observed [Formula: see text] variations cannot be explained by disorder effects.
    Language English
    Publishing date 2022-07-27
    Publishing country England
    Document type Journal Article
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-022-16355-4
    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.

  4. Article ; Online: Recyclable and Environmentally Friendly Magnetic Nanoparticles with Aggregation-Induced Emission Photosensitizer for Sustainable Bacterial Inactivation in Water.

    Yu, Eric Y / Chau, Joe H C / Lee, Michelle M S / Koo, Tsin Hei / Lortz, Rolf / Lam, Jacky W Y / Kwok, Ryan T K / Li, Yuanyuan / Tang, Ben Zhong

    ACS nano

    2024  Volume 18, Issue 3, Page(s) 1907–1920

    Abstract: Bacterial photodynamic inactivation based on the combined actions of photosensitizers, light, and oxygen presents a promising alternative for eliminating bacteria compared to conventional water disinfection methods. However, a significant challenge in ... ...

    Abstract Bacterial photodynamic inactivation based on the combined actions of photosensitizers, light, and oxygen presents a promising alternative for eliminating bacteria compared to conventional water disinfection methods. However, a significant challenge in this approach is the inability to retrieve photosensitizers after phototreatment, posing potential adverse environmental impacts. Additionally, conventional photosensitizers often exhibit limited photostability and photodynamic efficiency. This study addresses these challenges by employing an aggregation-induced emission (AIE) photosensitizer, iron oxide magnetic nanoparticles (Fe
    MeSH term(s) Photosensitizing Agents/pharmacology ; Photosensitizing Agents/therapeutic use ; Photochemotherapy/methods ; Anti-Bacterial Agents ; Magnetite Nanoparticles ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Nanoparticles
    Chemical Substances Photosensitizing Agents ; Anti-Bacterial Agents ; Magnetite Nanoparticles
    Language English
    Publishing date 2024-01-08
    Publishing country United States
    Document type Journal Article
    ISSN 1936-086X
    ISSN (online) 1936-086X
    DOI 10.1021/acsnano.3c05941
    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.

  5. Article: Discovery of superconductivity in Nb

    Balestra, Manuele D / Atanov, Omargeldi / Lefèvre, Robin / Blacque, Olivier / Ng, Yat Hei / Lortz, Rolf / von Rohr, Fabian O

    Journal of materials chemistry. C

    2022  Volume 10, Issue 32, Page(s) 11703–11709

    Abstract: We report on the discovery, structural analysis, and the physical properties of ... ...

    Abstract We report on the discovery, structural analysis, and the physical properties of Nb
    Language English
    Publishing date 2022-07-29
    Publishing country England
    Document type Journal Article
    ZDB-ID 2702245-6
    ISSN 2050-7534 ; 2050-7526
    ISSN (online) 2050-7534
    ISSN 2050-7526
    DOI 10.1039/d2tc01510b
    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.

  6. Article: A Simulation of the Effect of External and Internal Parameters on the Synthesis of a Carbyne with More than 6000 Atoms for Emerging Continuously Tunable Energy Barriers in CNT-Based Transistors.

    Wong, Chi Ho / Yeung, Yan Ming / Zhao, Xin / Law, Wing Cheung / Tang, Chak Yin / Mak, Chee Leung / Leung, Chi Wah / Shi, Lei / Lortz, Rolf

    Nanomaterials (Basel, Switzerland)

    2023  Volume 13, Issue 6

    Abstract: Transistors made up of carbon nanotube CNT have demonstrated excellent current-voltage characteristics which outperform some high-grade silicon-based transistors. A continuously tunable energy barrier across semiconductor interfaces is desired to make ... ...

    Abstract Transistors made up of carbon nanotube CNT have demonstrated excellent current-voltage characteristics which outperform some high-grade silicon-based transistors. A continuously tunable energy barrier across semiconductor interfaces is desired to make the CNT-based transistors more robust. Despite that the direct band gap of the carbyne inside a CNT can be widely tuned by strain, the size of the carbyne cannot be controlled easily. The production of a monoatomic chain with more than 6000 carbon atoms is an enormous technological challenge. To predict the optimal chain length of a carbyne in different molecular environments, we have developed a Monte Carlo model in which a finite-length carbyne with a size of 4000-15,000 atoms is encapsulated by a CNT at finite temperatures. Our simulation shows that the stability of the carbyne@nanotube is strongly influenced by the nature and porosity of the CNT, the external pressure, the temperature, and the chain length. We have observed an initiation of the chain-breaking process in a compressed carbyne@nanotube. Our work provides much-needed input for optimizing the carbyne length to produce carbon chains much longer than 6000 atoms at ~300 K. Design rules are proposed for synthesizing ~1% strained carbyne@(6,5)CNT as a component in CNT-based transistors to tune the energy barriers continuously.
    Language English
    Publishing date 2023-03-14
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2662255-5
    ISSN 2079-4991
    ISSN 2079-4991
    DOI 10.3390/nano13061048
    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.

  7. Book ; Online: Discovery of Superconductivity in Nb$_4$SiSb$_2$ with a V$_4$SiSb$_2$-Type Structure and Implications of Interstitial Doping on its Physical Properties

    Balestra, Manuele D. / Atanov, Omargeldi / Lefèvre, Robin / Blacque, Olivier / Ng, Yat Hei / Lortz, Rolf / von Rohr, Fabian O.

    2022  

    Abstract: We report on the discovery, structural analysis, and the physical properties of Nb$_4$SiSb$_2$ -- a hitherto unknown compound crystallizing in the V$_4$SiSb$_2$-type structure with the tetragonal space group $I4/mcm$ and unit cell parameters $a$ = 10 ... ...

    Abstract We report on the discovery, structural analysis, and the physical properties of Nb$_4$SiSb$_2$ -- a hitherto unknown compound crystallizing in the V$_4$SiSb$_2$-type structure with the tetragonal space group $I4/mcm$ and unit cell parameters $a$ = 10.3638(2) $\mathring{\mathrm{A}}$ and $c$ = 4.9151(2) $\mathring{\mathrm{A}}$. We find Nb$_4$SiSb$_2$ to be a metal undergoing a transition to a superconducting state at a critical temperature of $T_{\rm c} \approx$ 1.6 K. The bulk nature of the superconductivity in this material is confirmed by the observation of a well defined discontinuity in specific heat with a normalized specific heat jump of $\Delta C(T_{\rm c})/\gamma T_{\rm c} = 1.33\, {\rm mJ}\, {\rm mol}^{-1}\, {\rm K}^{-2}$. We find that for Nb$_4$SiSb$_2$, the unoccupied sites on the $4b$ Wyckoff position can be partially occupied with Cu, Pd, or Pt. Low-temperature resistivity measurements show transitions to superconductivity for all three compounds at $T_{\rm c} \approx\, 1.2\, {\rm K}$ for Nb$_4$Cu$_{0.2}$SiSb$_2$, and $T_{\rm c} \approx\, 0.8\, {\rm K}$ for Nb$_4$Pd$_{0.2}$SiSb$_2$ as well as for Nb$_4$Pt$_{0.14}$SiSb$_2$. The addition of electron-donor atoms into these void positions, henceforth, lowers the superconducting transition temperature in comparison to the parent compound.
    Keywords Condensed Matter - Superconductivity ; Condensed Matter - Materials Science
    Publishing date 2022-08-09
    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.

  8. Article ; Online: Nodal and Nematic Superconducting Phases in NbSe_{2} Monolayers from Competing Superconducting Channels.

    Cho, Chang-Woo / Lyu, Jian / An, Liheng / Han, Tianyi / Lo, Kwan To / Ng, Cheuk Yin / Hu, Jiaqi / Gao, Yuxiang / Li, Gaomin / Huang, Mingyuan / Wang, Ning / Schmalian, Jörg / Lortz, Rolf

    Physical review letters

    2022  Volume 129, Issue 8, Page(s) 87002

    Abstract: Transition metal dichalcogenides like 2H-NbSe_{2} in their two-dimensional (2D) form exhibit Ising superconductivity with the quasiparticle spins being firmly pinned in the direction perpendicular to the basal plane. This enables them to withstand ... ...

    Abstract Transition metal dichalcogenides like 2H-NbSe_{2} in their two-dimensional (2D) form exhibit Ising superconductivity with the quasiparticle spins being firmly pinned in the direction perpendicular to the basal plane. This enables them to withstand exceptionally high magnetic fields beyond the Pauli limit for superconductivity. Using field-angle-resolved magnetoresistance experiments for fields rotated in the basal plane we investigate the field-angle dependence of the upper critical field (H_{c2}), which directly reflects the symmetry of the superconducting order parameter. We observe a sixfold nodal symmetry superposed on a twofold symmetry. This agrees with theoretical predictions of a nodal topological superconducting phase near H_{c2}, together with a nematic superconducting state. We demonstrate that in NbSe_{2} such unconventional superconducting states can arise from the presence of several competing superconducting channels.
    Language English
    Publishing date 2022-05-24
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.129.087002
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Bonn / Germany

    Z 4' 58/153: Show issues

    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. Book ; Online: Simulation of environmental impacts on the synthesis of carbyne with more than 6000 atoms for emerging continuously tunable energy barriers in CNT-based transistors

    Wong, Chi Ho / Yeung, Yan Ming / Zhao, Xin / Law, Wing Cheung / Tang, Chak-yin / Mak, Chee Leung / Leung, Chi Wah / Shi, Lei / Lortz, Rolf

    2023  

    Abstract: Transistors made up of carbon nanotubes CNT have demonstrated excellent current-voltage characteristics which outperform some high-grade silicon-based transistors. A continuously tunable energy barrier across semiconductor interfaces is desired to make ... ...

    Abstract Transistors made up of carbon nanotubes CNT have demonstrated excellent current-voltage characteristics which outperform some high-grade silicon-based transistors. A continuously tunable energy barrier across semiconductor interfaces is desired to make the CNT-based transistors more robust. Despite the direct band gap of carbyne inside a CNT can be widely tuned by strain, the size of carbyne cannot be controlled easily. The production of a monoatomic chain with more than 6000 carbon atoms is an enormous technological challenge. To predict the optimal chain length of a carbyne in different molecular environments, we have developed a Monte Carlo model in which a finite-length carbyne with a size of 4000-15000 atoms is encapsulated by a CNT at finite temperatures. Our simulation shows that the stability of the carbyne@nanotube is strongly influenced by the nature and porosity of the CNT, the external pressure, the temperature and the chain length. We have observed an initiation of chain-breaking process in a compressed carbyne@nanotube. Our work provides much needed input for optimising the carbyne length to produce carbon chains much longer than 6000 atoms at ~300K. Design rules are proposed for synthesizing ~1% strained carbyne@(6,5)CNT as a component in CNT-based transistors to tune the energy barriers continuously.

    Comment: arXiv admin note: substantial text overlap with arXiv:2207.14558
    Keywords Condensed Matter - Materials Science
    Publishing date 2023-01-19
    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.

  10. Article ; Online: Evidence for the Fulde-Ferrell-Larkin-Ovchinnikov state in bulk NbS

    Cho, Chang-Woo / Lyu, Jian / Ng, Cheuk Yin / He, James Jun / Lo, Kwan To / Chareev, Dmitriy / Abdel-Baset, Tarob A / Abdel-Hafiez, Mahmoud / Lortz, Rolf

    Nature communications

    2021  Volume 12, Issue 1, Page(s) 3676

    Abstract: We present measurements of the magnetic torque, specific heat and thermal expansion of the bulk transition metal dichalcogenide (TMD) superconductor ... ...

    Abstract We present measurements of the magnetic torque, specific heat and thermal expansion of the bulk transition metal dichalcogenide (TMD) superconductor NbS
    Language English
    Publishing date 2021-06-16
    Publishing country England
    Document type Journal Article
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-021-23976-2
    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