Chiral orbital-angular momentum in the surface states of Bi 2Se 3

Seung Ryong Park; Jinhee Han; Chul Kim; Yoon Young Koh; Changyoung Kim; Hyungjun Lee; Hyoung Joon Choi; Jung Hoon Han; Kyung Dong Lee; Nam Jung Hur; Masashi Arita; Kenya Shimada; Hirofumi Namatame; Masaki Taniguchi

doi:10.1103/PhysRevLett.108.046805

Chiral orbital-angular momentum in the surface states of Bi ₂Se ₃

Seung Ryong Park, Jinhee Han, Chul Kim, Yoon Young Koh, Changyoung Kim, Hyungjun Lee, Hyoung Joon Choi, Jung Hoon Han, Kyung Dong Lee, Nam Jung Hur, Masashi Arita, Kenya Shimada, Hirofumi Namatame, Masaki Taniguchi

Department of Physics

Research output: Contribution to journal › Article › peer-review

117 Citations (Scopus)

Abstract

We performed angle-resolved photoemission (ARPES) experiments with circularly polarized light and first-principles density functional calculation with spin-orbit coupling to study surface states of a topological insulator Bi ₂Se ₃. We observed circular dichroism (CD) as large as 30% in the ARPES data with upper and lower Dirac cones showing opposite signs in CD. The observed CD is attributed to the existence of local orbital-angular momentum (OAM). First-principles calculation shows that OAM in the surface states is significant and is locked to the electron momentum in the opposite direction to the spin, forming chiral OAM states. Our finding opens a new possibility for strong light-induced spin-polarized current in surface states. We also provide a proof for local OAM origin of the CD in ARPES.

Original language	English
Article number	046805
Journal	Physical review letters
Volume	108
Issue number	4
DOIs	https://doi.org/10.1103/PhysRevLett.108.046805
Publication status	Published - 2012 Jan 25

All Science Journal Classification (ASJC) codes

Physics and Astronomy(all)

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10.1103/PhysRevLett.108.046805

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title = "Chiral orbital-angular momentum in the surface states of Bi 2Se 3 ",

abstract = "We performed angle-resolved photoemission (ARPES) experiments with circularly polarized light and first-principles density functional calculation with spin-orbit coupling to study surface states of a topological insulator Bi 2Se 3. We observed circular dichroism (CD) as large as 30% in the ARPES data with upper and lower Dirac cones showing opposite signs in CD. The observed CD is attributed to the existence of local orbital-angular momentum (OAM). First-principles calculation shows that OAM in the surface states is significant and is locked to the electron momentum in the opposite direction to the spin, forming chiral OAM states. Our finding opens a new possibility for strong light-induced spin-polarized current in surface states. We also provide a proof for local OAM origin of the CD in ARPES.",

author = "Park, {Seung Ryong} and Jinhee Han and Chul Kim and Koh, {Yoon Young} and Changyoung Kim and Hyungjun Lee and Choi, {Hyoung Joon} and Han, {Jung Hoon} and Lee, {Kyung Dong} and Hur, {Nam Jung} and Masashi Arita and Kenya Shimada and Hirofumi Namatame and Masaki Taniguchi",

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doi = "10.1103/PhysRevLett.108.046805",

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T1 - Chiral orbital-angular momentum in the surface states of Bi 2Se 3

AU - Park, Seung Ryong

AU - Han, Jinhee

AU - Kim, Chul

AU - Koh, Yoon Young

AU - Kim, Changyoung

AU - Lee, Hyungjun

AU - Choi, Hyoung Joon

AU - Han, Jung Hoon

AU - Lee, Kyung Dong

AU - Hur, Nam Jung

AU - Arita, Masashi

AU - Shimada, Kenya

AU - Namatame, Hirofumi

AU - Taniguchi, Masaki

PY - 2012/1/25

Y1 - 2012/1/25

N2 - We performed angle-resolved photoemission (ARPES) experiments with circularly polarized light and first-principles density functional calculation with spin-orbit coupling to study surface states of a topological insulator Bi 2Se 3. We observed circular dichroism (CD) as large as 30% in the ARPES data with upper and lower Dirac cones showing opposite signs in CD. The observed CD is attributed to the existence of local orbital-angular momentum (OAM). First-principles calculation shows that OAM in the surface states is significant and is locked to the electron momentum in the opposite direction to the spin, forming chiral OAM states. Our finding opens a new possibility for strong light-induced spin-polarized current in surface states. We also provide a proof for local OAM origin of the CD in ARPES.

AB - We performed angle-resolved photoemission (ARPES) experiments with circularly polarized light and first-principles density functional calculation with spin-orbit coupling to study surface states of a topological insulator Bi 2Se 3. We observed circular dichroism (CD) as large as 30% in the ARPES data with upper and lower Dirac cones showing opposite signs in CD. The observed CD is attributed to the existence of local orbital-angular momentum (OAM). First-principles calculation shows that OAM in the surface states is significant and is locked to the electron momentum in the opposite direction to the spin, forming chiral OAM states. Our finding opens a new possibility for strong light-induced spin-polarized current in surface states. We also provide a proof for local OAM origin of the CD in ARPES.

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Chiral orbital-angular momentum in the surface states of Bi ₂Se ₃

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