Two-dimensional charge order stabilized in clean polytype heterostructures

Suk Hyun Sung; Noah Schnitzer; Steve Novakov; Ismail El Baggari; Xiangpeng Luo; Jiseok Gim; Nguyen M Vu; Zidong Li; Todd H Brintlinger; Yu Liu; Wenjian Lu; Yuping Sun; Parag B Deotare; Kai Sun; Liuyan Zhao; Lena F Kourkoutis; John T Heron; Robert Hovden

doi:10.1038/s41467-021-27947-5

Two-dimensional charge order stabilized in clean polytype heterostructures

Nat Commun. 2022 Jan 20;13(1):413. doi: 10.1038/s41467-021-27947-5.

Authors

Suk Hyun Sung¹, Noah Schnitzer^{2

3}, Steve Novakov⁴, Ismail El Baggari^{5

6}, Xiangpeng Luo⁴, Jiseok Gim¹, Nguyen M Vu¹, Zidong Li⁷, Todd H Brintlinger⁸, Yu Liu⁹, Wenjian Lu⁹, Yuping Sun^{9

10

11}, Parag B Deotare^{7

12}, Kai Sun⁴, Liuyan Zhao⁴, Lena F Kourkoutis^{3

13}, John T Heron^{1

12}, Robert Hovden^{14

15}

Affiliations

¹ Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
² Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA.
³ Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA.
⁴ Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA.
⁵ Department of Physics, Cornell University, Ithaca, NY, 14853, USA.
⁶ Rowland Institute at Harvard, Cambridge, MA, 02142, USA.
⁷ Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, MI, 48109, USA.
⁸ Materials Science and Technology Division, U.S. Naval Research Laboratory, Washington, D.C., 20375, USA.
⁹ Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, 230031, Hefei, P. R. China.
¹⁰ High Magnetic Field Laboratory, Chinese Academy of Sciences, 230031, Hefei, P. R. China.
¹¹ Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, 210093, Nanjing, P. R. China.
¹² Applied Physics Program, University of Michigan, Ann Arbor, MI, 48109, USA.
¹³ School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA.
¹⁴ Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA. [email protected].
¹⁵ Applied Physics Program, University of Michigan, Ann Arbor, MI, 48109, USA. [email protected].

Abstract

Compelling evidence suggests distinct correlated electron behavior may exist only in clean 2D materials such as 1T-TaS₂. Unfortunately, experiment and theory suggest that extrinsic disorder in free standing 2D layers disrupts correlation-driven quantum behavior. Here we demonstrate a route to realizing fragile 2D quantum states through endotaxial polytype engineering of van der Waals materials. The true isolation of 2D charge density waves (CDWs) between metallic layers stabilizes commensurate long-range order and lifts the coupling between neighboring CDW layers to restore mirror symmetries via interlayer CDW twinning. The twinned-commensurate charge density wave (tC-CDW) reported herein has a single metal-insulator phase transition at ~350 K as measured structurally and electronically. Fast in-situ transmission electron microscopy and scanned nanobeam diffraction map the formation of tC-CDWs. This work introduces endotaxial polytype engineering of van der Waals materials to access latent 2D ground states distinct from conventional 2D fabrication.