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APRIL 2020        TAP TIMES          -8-



         Team produces “most accurate”
             3D images of 2D materials




        LOS ANGELES—A UCLA-led research
        team has produced in unprecedented
        detail experimental three-dimensional
        maps of the atoms in a so-called 2D
        material — matter that isn’t truly two-
        dimensional but is nearly flat because                  Image shows the 3D atomic coordinates of molybdenum
        it’s arranged in extremely thin layers,                 (blue), sulfur (yellow) and added rhenium (orange). A 2D
                                                                image is shown beneath the 3D model.
        no more than a few atoms thick.                                                                               (Dennis Kim, UCLA)

                                                                But using 2D materials in real-world ap-
        Research interest                                       plications would require a greater under-
        Although 2D-materials–based technologies                standing of their properties, and the ability
        have not yet been widely used in commer-                to control those properties.
        cial applications, the materials have been
        the subject of considerable research inter-
        est.                                                    A step forward
                                                                The new study, which was published in
        In the future, they could be the basis for              Nature Materials, could be a step forward
        semiconductors in ever smaller electronics,             in that effort.
        quantum computer components, more-ef-
        ficient batteries, or filters capable of ex-            The researchers showed that their 3D
        tracting freshwater from saltwater.                     maps of the material’s atomic structure
                                                                are precise to the picometer scale — mea-
        The promise of 2D materials comes from                  sured in one-trillionths of a meter.
        certain properties that differ from how
        the same elements or compounds behave                   They used their measurements to quantify
        when they appear in greater quantities.                 defects in the 2D material, which can af-
                                                                fect their electronic properties, as well as
                                                                to accurately assess those electronic prop-
        Quantum effects                                         erties.
        Those unique characteristics are influenced
        by quantum effects — phenomena occur-
        ring at extremely small scales that are                 Coordinates of individual atoms
        fundamentally different from the classical              “What’s unique about this research is that
        physics seen at larger scales.                          we determine the coordinates of individual
                                                                atoms in three dimensions without using

        For instance, when carbon is arranged in                any pre-existing models,” said correspond-
        an atomically thin layer to form 2D gra-                ing author Jianwei “John” Miao, a UCLA
        phene, it is stronger than steel, conducts              professor of physics and astronomy.
        heat better than any other known mate-
        rial, and has almost zero electrical resis-             “And our method can be used for all kinds
        tance.                                                  of 2D materials.”  See Page 10
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