Band Engineering of Dirac Surface States in Topological-Insulator-Based van der Waals Heterostructures

Cui-Zu Chang, Peizhe Tang, Xiao Feng, Kang Li, Xu-Cun Ma, Wenhui Duan, Ke He, and Qi-Kun Xue

Phys. Rev. Lett. 115, 136801 – Published 23 September 2015

Abstract

The existence of a gapless Dirac surface band of a three dimensional (3D) topological insulator (TI) is guaranteed by the nontrivial topological character of the bulk band, yet the surface band dispersion is mainly determined by the environment near the surface. In this Letter, through in situ angle-resolved photoemission spectroscopy and first-principles calculation on 3D TI-based van der Waals heterostructures, we demonstrate that one can engineer the surface band structures of 3D TIs by surface modifications without destroying their topological nontrivial property. The result provides an accessible method to independently control the surface and bulk electronic structures of 3D TIs, and sheds light on designing artificial topological materials for electronic and spintronic purposes.

Received 15 April 2015

DOI:https://doi.org/10.1103/PhysRevLett.115.136801

Authors & Affiliations

Cui-Zu Chang^1,2,*, Peizhe Tang¹, Xiao Feng^1,2, Kang Li², Xu-Cun Ma^1,4, Wenhui Duan^1,3,4,†, Ke He^1,4,‡, and Qi-Kun Xue^1,2,4

¹State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
²Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
³Institute of Advanced Study, Tsinghua University, Beijing 100084, China
⁴Collaborative Innovation Center of Quantum Matter, Beijing 100084, China

^*Corresponding author. czchang@mit.edu
^†Corresponding author. dwh@phys.tsinghua.edu.cn
^‡Corresponding author. kehe@mail.tsinghua.edu.cn

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 115, Iss. 13 — 25 September 2015

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Images

Figure 1
Schematics of the van der Waals growth of cover layers on 3D topological insulator thin films.
Reuse & Permissions
Figure 2
Dirac surface states engineering in 3D TI films when another 1 QL TI film is deposited on the surface. ARPES band structures and corresponding momentum distribution curves (MDCs) of (a) 10 QL ${Bi}_{2} {Se}_{3}$ , (b) 1 QL ${Bi}_{2} {Te}_{3} / 10 QL$ ${Bi}_{2} {Se}_{3}$ , (c) 10 QL ${Sb}_{2} {Te}_{3}$ , and (d) 1 QL ${Bi}_{2} {Te}_{3} / 10 QL$ ${Sb}_{2} {Te}_{3}$ . All the spectra were taken along the $\bar{Γ} − \bar{K}$ direction at $T \sim 150 K$ .
Reuse & Permissions
Figure 3
First-principles calculations for the artificially engineered Dirac surface states. The DFT band structures of (a) 6 QL ${Bi}_{2} {Te}_{3}$ , (b) 1 QL ${Sb}_{2} {Te}_{3} / 6 QL$ ${Bi}_{2} {Te}_{3}$ , (c) 6 QL ${Sb}_{2} {Te}_{3}$ , and (d) 1 QL ${Bi}_{2} {Te}_{3} / 6 QL$ ${Sb}_{2} {Te}_{3}$ . The red solid and hollow dots in (b) and (d) show the bands induced by the topmost layer 1 QL ${Sb}_{2} {Te}_{3}$ or ${Bi}_{2} {Te}_{3}$ .
Reuse & Permissions
Figure 4
(a) ARPES band map of 20 QL ${Bi}_{2} {Se}_{3}$ . (b) ARPES band map and (c) constant energy contours of the Dirac surface states of 1 BL $Bi (111) / 20 QL$ ${Bi}_{2} {Se}_{3}$ heterostructure. All the spectra were taken along the $\bar{Γ} − \bar{K}$ direction at room temperature. (d) Comparison of Dirac surface states momentum vector of 20 QL ${Bi}_{2} {Se}_{3}$ and 1 BL $Bi (111) / 20 QL$ ${Bi}_{2} {Se}_{3}$ . The dashed line is the fitting curve, whose slope indicates the Fermi group velocity of Dirac surface states in 20 QL ${Bi}_{2} {Se}_{3}$ and 1 BL $Bi (111) / 20 QL$ ${Bi}_{2} {Se}_{3}$ .
Reuse & Permissions
Figure 5
(a) STM images of $500 nm \times 500 nm$ taken from 1 BL $Bi (111) / 20 QL$ ${Bi}_{2} {Se}_{3}$ film. (b) High resolution STM images of $100 nm \times 100 nm$ taken from 0.5 BL $Bi (111) / 20 QL$ ${Bi}_{2} {Se}_{3}$ film, moiré patterns can be observed. (c) Simulated moiré patterns for 1 BL Bi(111) on top of ${Bi}_{2} {Se}_{3}$ films, and the schematic diagrams of the stacking pattern are shown on the left, including $A B^{1}$ , $A B^{2}$ , and AA stacking. (d)–(f) The corresponding calculated band structures. Fermi levels are set to zero. The top and bottom DSSs of 6 QL ${Bi}_{2} {Se}_{3}$ are marked by the yellow and blue dots, respectively. The red and cyan solid dots in the band structures stand for the contribution of the top 1 BL Bi(111) and topmost 1 QL of ${Bi}_{2} {Se}_{3}$ , respectively. (g) In-plane spin-momentum relationship of the constant energy contour whose energy is marked by the dashed line in (d) and spin texture of the experimental Fermi surface in 1 BL $Bi (111) / 20 QL$ ${Bi}_{2} {Se}_{3}$ . The arrows indicate the spin direction, $R$ means right-handed helicity, $L$ means left-handed helicity.
Reuse & Permissions

Physical Review Letters