Bismuth bromide (α-Bi4Br4) can demonstrate various exotic topological states, including higher-order topological insulator with hinge states and quantum spin Hall insulator with helical edge states. To date, α-Bi4Br4 nanowires can be obtained by using the exfoliation method from the bulk. However, it is still a great challenge to efficiently prepare α-Bi4Br4 nanowires suitable for potential applications, e.g., saturable absorber in ultrafast pulsed fiber lasers. Here, we report the controllable growth of α-Bi4Br4 thin films consisting of nanowires via molecular beam epitaxy technique. We show that the morphology of the α-Bi4Br4 nanowires depends on the growth temperature and BiBr3 flux. In addition, we also achieve α-Bi4Br4 nanowires on NbSe2 and gold substrates. Furthermore, we performed the saturable absorption property of α-Bi4Br4 thin films with a modulation depth of 21.58% and mode-locking at 1556.4 nm with a pulse width of 375 fs in the pulsed fiber lasers. Those results demonstrate the synthesis of quasi-1D topological material α-Bi4Br4, which is expected to be used for the fundamental research of topological physics and potential applications in optical devices.

1.
J.-J.
Zhou
,
W.
Feng
,
G.-B.
Liu
, and
Y.
Yao
, “
Topological edge states in single- and multi-layer Bi4Br4
,”
New. J. Phys.
17
(
1
),
015004
(
2015
).
2.
G.
Autes
,
A.
Isaeva
,
L.
Moreschini
,
J. C.
Johannsen
,
A.
Pisoni
,
R.
Mori
,
W.
Zhang
,
T. G.
Filatova
,
A. N.
Kuznetsov
,
L.
Forro
,
W.
Van den Broek
,
Y.
Kim
,
K. S.
Kim
,
A.
Lanzara
,
J. D.
Denlinger
,
E.
Rotenberg
,
A.
Bostwick
,
M.
Grioni
, and
O. V.
Yazyev
, “
A novel quasi-one-dimensional topological insulator in bismuth iodide beta-Bi4I4
,”
Nat. Mater.
15
(
2
),
154
(
2016
).
3.
A.
Pisoni
,
R.
Gaál
,
A.
Zeugner
,
V.
Falkowski
,
A.
Isaeva
,
H.
Huppertz
,
G.
Autès
,
O. V.
Yazyev
, and
L.
Forró
, “
Pressure effect and superconductivity in the β-Bi4I4 topological insulator
,”
Phys. Rev. B
95
(
23
),
235149
(
2017
).
4.
D.-Y.
Chen
,
D.-S.
Ma
,
Y.
Li
,
Z. Z.
Du
,
X.
Xiong
,
Y.
He
,
J.
Duan
,
J.
Han
,
D.
Chen
,
W.
Xiao
, and
Y.
Yao
, “
Quantum transport properties in single crystals of α-Bi4I4
,”
Phys. Rev. Mater.
2
(
11
),
114408
(
2018
).
5.
J.
Zhuang
,
J.
Li
,
Y.
Liu
,
D.
Mu
,
M.
Yang
,
Y.
Liu
,
W.
Zhou
,
W.
Hao
,
J.
Zhong
, and
Y.
Du
, “
Epitaxial growth of quasi-one-dimensional bismuth-halide chains with atomically sharp topological non-trivial edge states
,”
ACS Nano
15
(
9
),
14850
(
2021
).
6.
C.-H.
Hsu
,
X.
Zhou
,
Q.
Ma
,
N.
Gedik
,
A.
Bansil
,
V. M.
Pereira
,
H.
Lin
,
L.
Fu
,
S.-Y.
Xu
, and
T.-R.
Chang
, “
Purely rotational symmetry-protected topological crystalline insulator alpha-Bi4Br4
,”
2D Mater.
6
(
3
),
031004
(
2019
).
7.
P.
Mao
,
M.
Wang
,
D.
Ma
,
D.
Chen
,
C.-c.
Liu
,
X.
Li
,
J.
Zheng
,
Y.
Li
,
H.
Yang
, and
Q.
Wang
, “
Observation of the topologically originated edge states in large-gap quasi-one-dimensional a-Bi4Br4
,” arXiv:2007.00223 (
2020
).
8.
C. C.
Liu
,
J. J.
Zhou
,
Y.
Yao
, and
F.
Zhang
, “
Weak topological insulators and composite Weyl semimetals: Beta-Bi4X4 (X = Br, I)
,”
Phys. Rev. Lett.
116
(
6
),
066801
(
2016
).
9.
R.
Noguchi
,
T.
Takahashi
,
K.
Kuroda
,
M.
Ochi
,
T.
Shirasawa
,
M.
Sakano
,
C.
Bareille
,
M.
Nakayama
,
M. D.
Watson
,
K.
Yaji
,
A.
Harasawa
,
H.
Iwasawa
,
P.
Dudin
,
T. K.
Kim
,
M.
Hoesch
,
V.
Kandyba
,
A.
Giampietri
,
A.
Barinov
,
S.
Shin
,
R.
Arita
,
T.
Sasagawa
, and
T.
Kondo
, “
A weak topological insulator state in quasi-one-dimensional bismuth iodide
,”
Nature
566
(
7745
),
518
(
2019
).
10.
J.
Huang
,
S.
Li
,
C.
Yoon
,
J. S.
Oh
,
H.
Wu
,
X.
Liu
,
N.
Dhale
,
Y.-F.
Zhou
,
Y.
Guo
,
Y.
Zhang
,
M.
Hashimoto
,
D.
Lu
,
J.
Denlinger
,
X.
Wang
,
C. N.
Lau
,
R. J.
Birgeneau
,
F.
Zhang
,
B.
Lv
, and
M.
Yi
, “
Room-temperature topological phase transition in quasi-one-dimensional material Bi4I4
,”
Phys. Rev. X
11
(
3
),
031042
(
2021
).
11.
X.
Wang
,
J.
Wu
,
J.
Wang
,
T.
Chen
,
H.
Gao
,
P.
Lu
,
Q.
Chen
,
C.
Ding
,
J.
Wen
, and
J.
Sun
, “
Pressure-induced structural and electronic transitions in bismuth iodide
,”
Phys. Rev. B
98
(
17
),
174112
(
2018
).
12.
Y.
Qi
,
W.
Shi
,
P.
Werner
,
P. G.
Naumov
,
W.
Schnelle
,
L.
Wang
,
K. G.
Rana
,
S.
Parkin
,
S. A.
Medvedev
,
B.
Yan
, and
C.
Felser
, “
Pressure-induced superconductivity and topological quantum phase transitions in a quasi-one-dimensional topological insulator: Bi4I4
,”
npj Quantum Mater.
3
(
1
),
4
(
2018
).
13.
R.
Noguchi
,
M.
Kobayashi
,
Z.
Jiang
,
K.
Kuroda
,
T.
Takahashi
,
Z.
Xu
,
D.
Lee
,
M.
Hirayama
,
M.
Ochi
,
T.
Shirasawa
,
P.
Zhang
,
C.
Lin
,
C.
Bareille
,
S.
Sakuragi
,
H.
Tanaka
,
S.
Kunisada
,
K.
Kurokawa
,
K.
Yaji
,
A.
Harasawa
,
V.
Kandyba
,
A.
Giampietri
,
A.
Barinov
,
T. K.
Kim
,
C.
Cacho
,
M.
Hashimoto
,
D.
Lu
,
S.
Shin
,
R.
Arita
,
K.
Lai
,
T.
Sasagawa
, and
T.
Kondo
, “
Evidence for a higher-order topological insulator in a three-dimensional material built from van der Waals stacking of bismuth-halide chains
,”
Nat. Mater.
20
(
4
),
473
(
2021
).
14.
N.
Shumiya
,
M. S.
Hossain
,
J.-X.
Yin
,
Z.
Wang
,
M.
Litskevich
,
C.
Yoon
,
Y.
Li
,
Y.
Yang
,
Y.-X.
Jiang
, and
G.
Cheng
, “
Room-temperature quantum spin Hall edge state in a higher-order topological insulator Bi4Br4
,” arXiv:2110.05718 (
2021
).
15.
X.
Peng
,
X.
Zhang
,
X.
Dong
,
D.
Ma
,
D.
Chen
,
Y.
Li
,
J.
Li
,
J.
Han
,
Z.
Wang
,
C. C.
Liu
,
J.
Zhou
,
W.
Xiao
, and
Y.
Yao
, “
Observation of topological edge states on alpha-Bi4Br4 nanowires grown on TiSe2 substrates
,”
J. Phys. Chem. Lett.
12
,
10465
(
2021
).
16.
J. J.
Zhou
,
W.
Feng
,
C. C.
Liu
,
S.
Guan
, and
Y.
Yao
, “
Large-gap quantum spin Hall insulator in single layer bismuth monobromide Bi4Br4
,”
Nano Lett.
14
(
8
),
4767
(
2014
).
17.
M.
Yang
,
Y.
Liu
,
W.
Zhou
,
C.
Liu
,
D.
Mu
,
Y.
Liu
,
J.
Wang
,
W.
Hao
,
J.
Li
, and
J.
Zhong
, “
Large-gap quantum spin hall state and temperature-induced lifshitz transition in Bi4Br4
,” arXiv:2110.06658 (
2021
).
18.
E.
Dikarev
,
B.
Popovkin
, and
A.
Shevelkov
, “
New polymolecular bismuth monohalides. Synthesis and crystal structures of Bi4BrxI4−x (x = 1, 2, or 3)
,”
Russ. Chem. Bull.
50
(
12
),
2304
(
2001
).
19.
T. G.
Filatova
,
P. V.
Gurin
,
L.
Kloo
,
V. A.
Kulbachinskii
,
A. N.
Kuznetsov
,
V. G.
Kytin
,
M.
Lindsjo
, and
B. A.
Popovkin
, “
Electronic structure, galvanomagnetic and magnetic properties of the bismuth subhalides Bi4I4 and Bi4Br4
,”
J. Solid State Chem.
180
(
3
),
1103
(
2007
).
20.
X.
Li
,
D.
Chen
,
M.
Jin
,
D.
Ma
,
Y.
Ge
,
J.
Sun
,
W.
Guo
,
H.
Sun
,
J.
Han
,
W.
Xiao
,
J.
Duan
,
Q.
Wang
,
C. C.
Liu
,
R.
Zou
,
J.
Cheng
,
C.
Jin
,
J.
Zhou
,
J. B.
Goodenough
,
J.
Zhu
, and
Y.
Yao
, “
Pressure-induced phase transitions and superconductivity in a quasi-1-dimensional topological crystalline insulator alpha-Bi4Br4
,”
Proc. Natl. Acad. Sci. U. S. A.
116
(
36
),
17696
(
2019
).
21.
L.
Qiao
,
X.
Xiong
,
H.
Yang
,
D.
Chen
,
Y.
Li
,
J.
Li
,
X.
Peng
,
Z.
Xu
,
J.
Han
,
W.
Xiao
, and
Y.
Yao
, “
Ultralong single-crystal α-Bi4Br4 nanobelts with a high current-carrying capacity by mechanical exfoliation
,”
J. Phys. Chem. C
125
(
40
),
22312
(
2021
).
22.
C.
Zhao
,
H.
Zhang
,
X.
Qi
,
Y.
Chen
,
Z.
Wang
,
S.
Wen
, and
D.
Tang
, “
Ultra-short pulse generation by a topological insulator based saturable absorber
,”
Appl. Phys. Lett.
101
(
21
),
211106
(
2012
).
23.
C.
Zhao
,
Y.
Zou
,
Y.
Chen
,
Z.
Wang
,
S.
Lu
,
H.
Zhang
,
S.
Wen
, and
D.
Tang
, “
Wavelength-tunable picosecond soliton fiber laser with topological insulator: Bi2Se3 as a mode locker
,”
Opt. Express
20
(
25
),
27888
(
2012
).
24.
H.
Zhang
,
X.
He
,
W.
Lin
,
R.
Wei
,
F.
Zhang
,
X.
Du
,
G.
Dong
, and
J.
Qiu
, “
Ultrafast saturable absorption in topological insulator Bi2SeTe2 nanosheets
,”
Opt. Express
23
(
10
),
13376
(
2015
).
25.
X.
He
,
H.
Zhang
,
W.
Lin
,
R.
Wei
,
J.
Qiu
,
M.
Zhang
, and
B.
Hu
, “
PVP-assisted solvothermal synthesis of high-yielded Bi2Te3 hexagonal nanoplates: Application in passively Q-switched fiber laser
,”
Sci. Rep.
5
(
1
),
15868
(
2015
).
26.
H.
Yu
,
H.
Zhang
,
Y.
Wang
,
C.
Zhao
,
B.
Wang
,
S.
Wen
,
H.
Zhang
, and
J.
Wang
, “
Topological insulator as an optical modulator for pulsed solid-state lasers
,”
Laser Photonics Rev.
7
(
6
),
L77
(
2013
).
27.
X.
Dong
,
Y.
Li
,
J.
Li
,
X.
Peng
,
L.
Qiao
,
D.
Chen
,
H.
Yang
,
X.
Xiong
,
Q.
Wang
,
X.
Li
,
J.
Duan
,
J.
Han
, and
W.
Xiao
, “
Epitaxial growth and structural properties of Bi(110) thin films on TiSe2 substrates
,”
J. Phys. Chem. C
123
(
22
),
13637
(
2019
).
28.
Y.
Chen
,
C.
Zhao
,
S.
Chen
,
J.
Du
,
P.
Tang
,
G.
Jiang
,
H.
Zhang
,
S.
Wen
, and
D.
Tang
, “
Large energy, wavelength widely tunable, topological insulator Q-switched erbium-doped fiber laser
,”
IEEE J. Sel. Top. Quantum Electron
20
(
5
),
315
(
2013
).

Supplementary Material

You do not currently have access to this content.