PMID- 37490531
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20230807
IS  - 1091-6490 (Electronic)
IS  - 0027-8424 (Print)
IS  - 0027-8424 (Linking)
VI  - 120
IP  - 31
DP  - 2023 Aug
TI  - Optically controlled single-valley exciton doublet states with tunable internal 
      spin structures and spin magnetization generation.
PG  - e2307611120
LID - 10.1073/pnas.2307611120 [doi]
LID - e2307611120
AB  - Manipulating quantum states through light-matter interactions has been actively 
      pursued in two-dimensional materials research. Significant progress has been made 
      toward the optical control of the valley degrees of freedom in semiconducting 
      monolayer transition-metal dichalcogenides, based on doubly degenerate excitons 
      from their two distinct valleys in reciprocal space. Here, we introduce a type of 
      optically controllable doubly degenerate exciton states that come from a single 
      valley, dubbed as single-valley exciton doublet (SVXD) states. They are unique in 
      that their constituent holes originate from the same valence band, making 
      possible the direct optical control of the spin structure of the excited 
      constituent electrons. Combining ab initio GW plus Bethe-Salpeter equation 
      (GW-BSE) calculations and a theoretical analysis method, we demonstrate such SVXD 
      in substrate-supported monolayer bismuthene-which has been successfully grown 
      using molecular beam epitaxy. In each of the two distinct valleys in the 
      Brillouin zone, strong spin-orbit coupling and [Formula: see text] symmetry lead 
      to a pair of degenerate 1s exciton states (the SVXD states) with opposite spin 
      configurations. Any coherent linear combinations of the SVXD in a single valley 
      can be excited by light with a specific polarization, enabling full manipulation 
      of their internal spin configurations. In particular, a controllable net spin 
      magnetization can be generated through light excitation. Our findings open routes 
      to control quantum degrees of freedom, paving the way for applications in 
      spintronics and quantum information science.
FAU - Ruan, Jiawei
AU  - Ruan J
AD  - Department of Physics, University of California at Berkeley, Berkeley, CA 94720.
AD  - Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 
      94720.
FAU - Li, Zhenglu
AU  - Li Z
AD  - Department of Physics, University of California at Berkeley, Berkeley, CA 94720.
AD  - Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 
      94720.
FAU - Ong, Chin Shen
AU  - Ong CS
AD  - Department of Physics, University of California at Berkeley, Berkeley, CA 94720.
AD  - Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 
      94720.
FAU - Louie, Steven G
AU  - Louie SG
AUID- ORCID: 0000-0003-0622-0170
AD  - Department of Physics, University of California at Berkeley, Berkeley, CA 94720.
AD  - Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 
      94720.
LA  - eng
GR  - DE-AC02- 05CH11231/U.S. Department of Energy (DOE)/
PT  - Journal Article
DEP - 20230725
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
SB  - IM
PMC - PMC10401001
OTO - NOTNLM
OT  - 2D materials
OT  - excitonic effects
OT  - first principles
OT  - spins
COIS- The authors declare no competing interest.
EDAT- 2023/07/25 19:15
MHDA- 2023/07/25 19:16
PMCR- 2023/07/25
CRDT- 2023/07/25 14:03
PHST- 2023/07/25 19:16 [medline]
PHST- 2023/07/25 19:15 [pubmed]
PHST- 2023/07/25 14:03 [entrez]
PHST- 2023/07/25 00:00 [pmc-release]
AID - 202307611 [pii]
AID - 10.1073/pnas.2307611120 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 2023 Aug;120(31):e2307611120. doi: 
      10.1073/pnas.2307611120. Epub 2023 Jul 25.