Spin-polarized spatially indirect excitons in a topological insulator

Ryo Mori (), Samuel Ciocys, Kazuaki Takasan, Ping Ai, Kayla Currier, Takahiro Morimoto, Joel E. Moore and Alessandra Lanzara ()
Additional contact information
Ryo Mori: Lawrence Berkeley National Laboratory
Samuel Ciocys: Lawrence Berkeley National Laboratory
Kazuaki Takasan: Lawrence Berkeley National Laboratory
Ping Ai: Lawrence Berkeley National Laboratory
Kayla Currier: Lawrence Berkeley National Laboratory
Takahiro Morimoto: The University of Tokyo
Joel E. Moore: Lawrence Berkeley National Laboratory
Alessandra Lanzara: Lawrence Berkeley National Laboratory

Nature, 2023, vol. 614, issue 7947, 249-255

Abstract: Abstract The exciton, a bound state of an electron and a hole, is a fundamental quasiparticle induced by coherent light–matter interactions in semiconductors. When the electrons and holes are in distinct spatial locations, spatially indirect excitons are formed with a much longer lifetime and a higher condensation temperature. One of the ultimate frontiers in this field is to create long-lived excitonic topological quasiparticles by driving exciton states with topological properties, to simultaneously leverage both topological effects and correlation1,2. Here we reveal the existence of a transient excitonic topological surface state (TSS) in a topological insulator, Bi2Te3. By using time-, spin- and angle-resolved photoemission spectroscopy, we directly follow the formation of a long-lived exciton state as revealed by an intensity buildup below the bulk-TSS mixing point and an anomalous band renormalization of the continuously connected TSS in the momentum space. Such a state inherits the spin-polarization of the TSS and is spatially indirect along the z axis, as it couples photoinduced surface electrons and bulk holes in the same momentum range, which ultimately leads to an excitonic state of the TSS. These results establish Bi2Te3 as a possible candidate for the excitonic condensation of TSSs3 and, in general, opens up a new paradigm for exploring the momentum space emergence of other spatially indirect excitons, such as moiré and quantum well excitons4–6, and for the study of non-equilibrium many-body topological physics.

Date: 2023
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/s41586-022-05567-3 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:614:y:2023:i:7947:d:10.1038_s41586-022-05567-3

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-022-05567-3

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().