• On the hunt for ultra-thin materials usi

    From ScienceDaily@1:317/3 to All on Thu Mar 10 21:30:40 2022
    On the hunt for ultra-thin materials using data mining

    Date:
    March 10, 2022
    Source:
    Helmholtz-Zentrum Dresden-Rossendorf
    Summary:
    Two-dimensional (2D) materials possess extraordinary
    properties. They usually consist of atomic layers that are only a
    few nanometers thick and are particularly good at conducting heat
    and electricity, for instance.

    To the astonishment of many scientists, it recently became known
    that 2D materials can also exist on the basis of certain metal
    oxides. These oxides are of great interest in areas such as
    nanoelectronics applications. A research team has now succeeded
    in predicting twenty- eight representatives of this new class of
    materials by using data-driven methods.



    FULL STORY ========================================================================== Two-dimensional (2D) materials possess extraordinary properties. They
    usually consist of atomic layers that are only a few nanometers
    thick and are particularly good at conducting heat and electricity,
    for instance. To the astonishment of many scientists, it recently
    became known that 2D materials can also exist on the basis of certain
    metal oxides. These oxides are of great interest in areas such as nanoelectronics applications. A German-American research team, led by
    the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), has now succeeded in predicting twenty-eight representatives of this new class of materials
    by using data-driven methods.


    ========================================================================== There is a substantial difference between conventional 2D materials
    such as graphene and the novel materials that can be synthesized from
    metal oxides such as ilmenite and chromite. The latter do not form weak interactions -- what are known as van der Waals forces -- in their
    crystal structure, but instead form stronger ionic bonds that point
    in all directions. For this reason, only a few experiments have so far succeeded in detaching novel 2D materials from 3D material blocks. The
    results of the study can now lead to success in further experiments
    of this type. Using theoretical methods, the scientists predict which
    compounds are actually worthwhile for experimental research.

    "With our data driven method, we built upon the first available
    information from the initial experiments. From this information,
    we developed structural prototypes and then ran them through a huge
    materials database as a filter criterion," explains the leader of the
    study, Dr. Rico Friedrich from the HZDR Institute of Ion Beam Physics
    and Materials Research. "The main challenge was figuring out why these materials form 2D systems so easily with particular oxides. From this information, we were able to develop a valid generalized search criterion
    and could systematically characterize the identified candidates according
    to their properties." For this purpose, the researchers primarily applied
    what is known as "density functional theory," a practical computational
    method for electronic structures that is widely used in quantum chemistry
    and in condensed matter physics. They collaborated with several German high-performance data centers for the necessary computing stages. A
    decisive factor was determining the exfoliation energy: this defines
    how much energy must be expended to remove a 2D layer from the surface
    of a material.

    Materials database with approximately 3.5 million entries The study
    also utilized the AFLOW materials database (Automatic Flow for Materials Discovery). It has been under development for more than twenty years by
    Prof. Stefano Curtarolo from Duke University (USA), who also contributed
    as author of the study. AFLOW is regarded as one of the largest materials science databases and classifies approximately 3.5 million compounds
    with more than 700 million calculated material properties.

    Together with the associated software, the database ultimately provided
    the researchers with not only the chemical composition of twenty-eight 2D-capable materials, but also enabled them to study their properties,
    which are remarkable in electronic and magnetic as well as topological respects.

    According to Rico Friedrich, their specific magnetic surface structures
    could make them particularly attractive for spintronic applications,
    such as for data storage in computers and smartphones.

    "I'm certain that we can find additional 2D materials of this kind," says
    the Dresden physicist, casting a glance into the future. "With enough candidates, perhaps even a dedicated database could be created entirely specialized in this new class of materials." The HZDR scientists remain
    in close contact with colleagues from a subject-related collaborative
    research center (Sonderforschungsbereich) at the TU Dresden as well as
    with the leading research group for synthesizing novel 2D systems in the
    United States. Together with both partners, they plan to pursue further
    study of the most promising compounds.


    ========================================================================== Story Source: Materials provided by
    Helmholtz-Zentrum_Dresden-Rossendorf. Note: Content may be edited for
    style and length.


    ========================================================================== Journal Reference:
    1. Rico Friedrich, Mahdi Ghorbani-Asl, Stefano Curtarolo, Arkady V.

    Krasheninnikov. Data-Driven Quest for Two-Dimensional Non-van der
    Waals Materials. Nano Letters, 2022; 22 (3): 989 DOI: 10.1021/
    acs.nanolett.1c03841 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220310115129.htm

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