Research in the Gweon Group
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| This is a very intersting topic, in many ways, at this moment. First, this is a simple quantum phase of matter, recently proposed theoretically and ''discovered.'' Second, no bulk isulator has been really confirmed to be a topological insulator, so far, perhaps with the exception of SmB$_6$. Most so-called ''toplogical insulator'' materials are bulk metals, not bulk insulators, as strictly required for topological insulators. Third, the ARPES data have been crucial in ascertaining the ''topological insulator nature'' of these materials. | This is a very intersting topic, in many ways. Topological insulator is a new quantum phase of matter, recently proposed theoretically. It is required to be a bulk insulator and a topologically protected surface metal. ARPES data have been crucial in ascertaining the topological insulator nature of various materials, now accepted as topological insulators, even though the bulk crystal of many of these materials has remnant charge carriers and thus is not an insulator. The protected surface state has a strong similarity to the electronic structure of graphene, whose “Dirac-cone” electronic structure was measured by ARPES for the first time, in an experiment led by [[publist#ref:rollings_synthesis_2006|G.-H. Gweon]]. |
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| Here in UCSC, we are studying these materials from two different perspectives. First, we are studying the interaction effects in topological insulators. Second, the surface metallic state in topological insulator materials seems a very good reference to use to compare with anomalous line shapes in quasi-two-dimensional and quasi-one-dimenasional cuprates, that the Gweon group study. | <<h(<div style="width=40%; float: right; vertical-align: top; padding-top: 0.25em; padding-bottom: 0.5em; padding-right: 0em; padding-left: 1.5em;">)>>{{https://upload.wikimedia.org/wikipedia/commons/thumb/f/fd/Topological_insulator_band_structure.svg/300px-Topological_insulator_band_structure.svg.png|TBI band structure|width=100%}} <<h(</div>)>> Here at UCSC, we are studying these materials from two different perspectives. First, we are studying interaction effects in topological insulators. Second, the surface metallic state in topological insulator materials seems a very good reference to compare with anomalous line shapes in quasi-two-dimensional and quasi-one-dimenasional cuprates that our group study. |
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| == Students == | == Links, Students == * Here is <<la(Reichwein_TI_draft.pdf, "a draft paper by Eric Reichwein")>>. Eric's thesis <<ln(http://ericreichwein.com/research/ReichweinThesisTI.pdf, "is available here also")>>. |
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| * A summer intern from high school, Richelle Smith, helped with this project during the summer of 2012. | * A summer intern from high school, Richelle Smith, helped with this project. |
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| * Gregory Kaminsky has been helpful in discussions of topological insulator. | * Gregory Kaminsky (grad student) has been helpful in discussions of topological insulator. |
Topological insulator
This is a very intersting topic, in many ways. Topological insulator is a new quantum phase of matter, recently proposed theoretically. It is required to be a bulk insulator and a topologically protected surface metal. ARPES data have been crucial in ascertaining the topological insulator nature of various materials, now accepted as topological insulators, even though the bulk crystal of many of these materials has remnant charge carriers and thus is not an insulator. The protected surface state has a strong similarity to the electronic structure of graphene, whose “Dirac-cone” electronic structure was measured by ARPES for the first time, in an experiment led by G.-H. Gweon.
Links, Students
Here is a draft paper by Eric Reichwein. Eric's thesis is available here also.
- Ahram Kim (grad student) and Eric Reichwein (undergrad student) are woking on this project.
- A summer intern from high school, Richelle Smith, helped with this project.
- Gregory Kaminsky (grad student) has been helpful in discussions of topological insulator.