Publication Date:
2013-03-09
Description:
Relativistic quantum mechanics predicts that when the charge of a superheavy atomic nucleus surpasses a certain threshold, the resulting strong Coulomb field causes an unusual atomic collapse state; this state exhibits an electron wave function component that falls toward the nucleus, as well as a positron component that escapes to infinity. In graphene, where charge carriers behave as massless relativistic particles, it has been predicted that highly charged impurities should exhibit resonances corresponding to these atomic collapse states. We have observed the formation of such resonances around artificial nuclei (clusters of charged calcium dimers) fabricated on gated graphene devices via atomic manipulation with a scanning tunneling microscope. The energy and spatial dependence of the atomic collapse state measured with scanning tunneling microscopy revealed unexpected behavior when occupied by electrons.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wang, Yang -- Wong, Dillon -- Shytov, Andrey V -- Brar, Victor W -- Choi, Sangkook -- Wu, Qiong -- Tsai, Hsin-Zon -- Regan, William -- Zettl, Alex -- Kawakami, Roland K -- Louie, Steven G -- Levitov, Leonid S -- Crommie, Michael F -- New York, N.Y. -- Science. 2013 May 10;340(6133):734-7. doi: 10.1126/science.1234320. Epub 2013 Mar 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23470728" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
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Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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