The interface atomic structure between an epitaxial thin film of the prototype topological semimetal cadmium arsenide (Cd3As2) and a III–V semiconductor layer is investigated using high-angle annular dark-field imaging in an aberration-corrected scanning transmission electron microscope. We find that the interface unit cell adopts a defined stoichiometry that is CdSb-like, which is achieved through the insertion of periodically arranged Cd vacancies in the terminating Cd-plane of Cd3As2. This interface stoichiometry is consistent with the Sb-termination of the III–V layer and the fact that CdSb is the thermodynamically stable phase in the Cd–Sb binary system. We find at least two distinct alignments of the film with respect to the buffer layer, which are characterized by a 1 4 100 Cd 3 As 2 shift parallel to the interface. We show that steps of half unit cell height in the III–V layer can produce these distinct interface structures.

1.
Z. J.
Wang
,
H. M.
Weng
,
Q. S.
Wu
,
X.
Dai
, and
Z.
Fang
, “
Three-dimensional Dirac semimetal and quantum transport in Cd3As2
,”
Phys. Rev. B
88
,
125427
(
2013
).
2.
M. N.
Ali
,
Q.
Gibson
,
S.
Jeon
,
B. B.
Zhou
,
A.
Yazdani
, and
R. J.
Cava
, “
The crystal and electronic structures of Cd3As2, the three-dimensional electronic analogue of graphene
,”
Inorg. Chem.
53
,
4062
4067
(
2014
).
3.
S.
Borisenko
,
Q.
Gibson
,
D.
Evtushinsky
,
V.
Zabolotnyy
,
B.
Buchner
, and
R. J.
Cava
, “
Experimental realization of a three-dimensional Dirac semimetal
,”
Phys. Rev. Lett.
113
,
027603
(
2014
).
4.
T.
Liang
,
Q.
Gibson
,
M. N.
Ali
,
M. H.
Liu
,
R. J.
Cava
, and
N. P.
Ong
, “
Ultrahigh mobility and giant magnetoresistance in the Dirac semimetal Cd3As2
,”
Nat. Mater.
14
,
280
284
(
2015
).
5.
S.
Jeon
,
B. B.
Zhou
,
A.
Gyenis
,
B. E.
Feldman
,
I.
Kimchi
,
A. C.
Potter
,
Q. D.
Gibson
,
R. J.
Cava
,
A.
Vishwanath
, and
A.
Yazdani
, “
Landau quantization and quasiparticle interference in the three-dimensional Dirac semimetal Cd3As2
,”
Nat. Mater.
13
,
851
856
(
2014
).
6.
M.
Neupane
,
S. Y.
Xu
,
R.
Sankar
,
N.
Alidoust
,
G.
Bian
,
C.
Liu
,
I.
Belopolski
,
T. R.
Chang
,
H. T.
Jeng
,
H.
Lin
,
A.
Bansil
,
F.
Chou
, and
M. Z.
Hasan
, “
Observation of a three-dimensional topological Dirac semimetal phase in high-mobility Cd3As2
,”
Nat. Commun.
5
,
3786
(
2014
).
7.
L.
Galletti
,
T.
Schumann
,
O. F.
Shoron
,
M.
Goyal
,
D. A.
Kealhofer
,
H.
Kim
, and
S.
Stemmer
, “
Two-dimensional Dirac fermions in thin films of Cd3As2
,”
Phys. Rev. B
97
,
115132
(
2018
).
8.
D. A.
Kealhofer
,
L.
Galletti
,
T.
Schumann
,
A.
Suslov
, and
S.
Stemmer
, “
Topological insulator state and collapse of the quantum Hall effect in a three-dimensional Dirac semimetal heterojunction
,”
Phys. Rev. X
10
,
011050
(
2020
).
9.
A. C.
Lygo
,
B.
Guo
,
A.
Rashidi
,
V.
Huang
,
P.
Cuadros-Romero
, and
S.
Stemmer
, “
Two-dimensional topological insulator state in cadmium arsenide thin films
,”
Phys. Rev. Lett.
130
,
046201
(
2023
).
10.
B.
Guo
,
W.
Miao
,
V.
Huang
,
A. C.
Lygo
,
X.
Dai
, and
S.
Stemmer
, “
Zeeman field-induced two-dimensional Weyl semimetal phase in cadmium arsenide
,”
Phys. Rev. Lett.
131
,
046601
(
2023
).
11.
T.
Schumann
,
M.
Goyal
,
H.
Kim
, and
S.
Stemmer
, “
Molecular beam epitaxy of Cd3As2 on a III-V substrate
,”
APL Mater.
4
,
126110
(
2016
).
12.
D. A.
Kealhofer
,
H.
Kim
,
T.
Schumann
,
M.
Goyal
,
L.
Galletti
, and
S.
Stemmer
, “
Basal-plane growth of cadmium arsenide by molecular beam epitaxy
,”
Phys. Rev. Mater.
3
,
031201
(
2019
).
13.
M.
Goyal
,
S.
Salmani-Rezaie
,
T. N.
Pardue
,
B. H.
Guo
,
D. A.
Kealhofer
, and
S.
Stemmer
, “
Carrier mobilities of (001) cadmium arsenide films
,”
APL Mater.
8
,
051106
(
2020
).
14.
R.
Xiao
,
J.
Zhang
,
J.
Chamorro
,
J.
Kim
,
T. M.
McQueen
,
D.
Vanderbilt
,
M.
Kayyalha
,
Y.
Li
, and
N.
Samarth
, “
Integer quantum Hall effect and enhanced g factor in quantum-confined Cd3As2 films
,”
Phys. Rev. B
106
,
L201101
(
2022
).
15.
M.
Goyal
,
L.
Galletti
,
S.
Salmani-Rezaie
,
T.
Schumann
,
D. A.
Kealhofer
, and
S.
Stemmer
, “
Thickness dependence of the quantum Hall effect in films of the three-dimensional Dirac semimetal Cd3As2
,”
APL Mater.
6
,
026105
(
2018
).
16.
A. D.
Rice
,
K.
Park
,
E. T.
Hughes
,
K.
Mukherjee
, and
K.
Alberi
, “
Defects in Cd3As2 epilayers via molecular beam epitaxy and strategies for reducing them
,”
Phys. Rev. Mater.
3
,
121201
(
2019
).
17.
G.
Tuttle
,
H.
Kroemer
, and
J. H.
English
, “
Effects of interface layer sequencing on the transport properties of InAs/AlSb quantum wells: Evidence for antisite donors at the InAs/AlSb interface
,”
J. Appl. Phys.
67
,
3032
3037
(
1990
).
18.
S.
Tchoumakov
,
V.
Jouffrey
,
A.
Inhofer
,
E.
Bocquillon
,
B.
Placais
,
D.
Carpentier
, and
M. O.
Goerbig
, “
Volkov-Pankratov states in topological heterojunctions
,”
Phys. Rev. B
96
,
201302
(
2017
).
19.
D. A.
Kealhofer
,
R.
Kealhofer
,
D.
Ohara
,
T. N.
Pardue
, and
S.
Stemmer
, “
Controlling and visualizing Dirac physics in topological semimetal heterostructures
,”
Sci. Adv.
8
,
eabn4479
(
2022
).
20.
H.
Kim
,
M.
Goyal
,
S.
Salmani-Rezaie
,
T.
Schumann
,
T. N.
Pardue
,
J.-M.
Zuo
, and
S.
Stemmer
, “
Point group symmetry of cadmium arsenide thin films determined by convergent beam electron diffraction
,”
Phys. Rev. Mater.
3
,
084202
(
2019
).
21.
T. N.
Pardue
,
M.
Goyal
,
B.
Guo
,
S.
Salmani-Rezaie
,
H.
Kim
,
O.
Heinonen
,
M. D.
Johannes
, and
S.
Stemmer
, “
Controlling the symmetry of cadmium arsenide films by epitaxial strain
,”
APL Mater.
9
,
051111
(
2021
).
22.
G. A.
Steigmann
and
J.
Goodyear
, “
The crystal structure of Cd3As2
,”
Acta Cryst.
B24
,
1062
1067
(
1968
).
23.
B. H.
Guo
,
A. C.
Lygo
,
T. N.
Pardue
, and
S.
Stemmer
, “
Hall bar measurements of topological surface states of (001) cadmium arsenide thin films interfaced with superconductors
,”
Phys. Rev. Mater.
6
,
034203
(
2022
).
24.
J. M.
LeBeau
,
S. D.
Findlay
,
L. J.
Allen
, and
S.
Stemmer
, “
Position averaged convergent beam electron diffraction: Theory and applications
,”
Ultramicroscopy
110
,
118
125
(
2010
).
25.
A. J.
McAlister
, “
The Al−Cd (aluminum−cadmium) system
,”
Bull. Alloy Phase Diagrams
3
,
172
177
(
1982
).
26.
D. O.
Klenov
,
L. F.
Edge
,
D. G.
Schlom
, and
S.
Stemmer
, “
Extended defects in epitaxial Sc2O3 films grown on (111) Si
,”
Appl. Phys. Lett.
86
,
051901
(
2005
).
27.
D. N.
Nasledov
and
V. Y.
Shevchen
, “
Semiconducting AIIBV compounds
,”
Phys. Status Solidi A
15
,
9
(
1973
).

Supplementary Material

You do not currently have access to this content.