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Charge Transfer Effects in Naturally Occurring van der Waals Heterostructures ( PbSe ) 1.16 ( TiSe 2 ) m ( m = 1 , 2)

DOI: 10.1103/PhysRevLett.120.106401 DOI Help

Authors: Q. Yao (Fudan University; Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences; 3Collaborative Innovation Centre of Advanced Microstructures) , D. W. Shen (Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences; CAS Center for Excellence in Superconducting Electronics (CENSE)) , C. H. P. Wen (Fudan University; Collaborative Innovation Centre of Advanced Microstructures) , C. Q. Hua (Zhejiang University) , L. Q. Zhang (Collaborative Innovation Centre of Advanced Microstructures; Nanjing University) , N. Z. Wang (University of Science and Technology of China) , X. H. Niu (Fudan University) , Q. Y. Chen (Fudan University; Collaborative Innovation Centre of Advanced Microstructures) , P. Dudin (Diamond Light Source) , Y. H. Lu (Zhejiang University) , Y. Zheng (Zhejiang University) , X. H. Chen (Collaborative Innovation Centre of Advanced Microstructures; University of Science and Technology of China; High Magnetic Field Laboratory, Chinese Academy of Sciences) , X. G. Wan (Collaborative Innovation Centre of Advanced Microstructures; Nanjing University) , D. L. Feng (Fudan University; Collaborative Innovation Centre of Advanced Microstructures)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review Letters , VOL 120

State: Published (Approved)
Published: March 2018
Diamond Proposal Number(s): 14737

Abstract: van der Waals heterostructures (vdWHs) exhibit rich properties and thus potential for applications, and charge transfer between different layers in a heterostructure often dominates its properties and device performance. It is thus critical to reveal and understand the charge transfer effects in vdWHs, for which electronic structure measurements have proven to be effective. Using angle-resolved photoemission spectroscopy, we studied the electronic structures of (PbSe)1.16(TiSe2)m (m = 1, 2), which are naturally occurring vdWHs, and discovered several striking charge transfer effects, which may widely exist in vdWHs. When the thickness of the TiSe2 lay- ers is halved from m = 2 to m = 1, the amount of charge transfered increases unexpectedly by more than 250 %. This is accompanied by a dramatic drop in the electron-phonon interaction strength far beyond the prediction by first-principles calculations and, consequently, superconductivity only exists in the m = 2 compound with strong electron-phonon interaction, albeit with lower carrier density. Furthermore, we found that the amount of charge transfered in both compounds is nearly halved when warmed from below 10 K to room temperature, due to the different thermal expansion coefficients of the constituent layers of these misfit compounds. These un- precedentedly large charge transfer effects provide important insights for further understanding and application of devices based on vdWHs.

Subject Areas: Physics, Materials


Instruments: I05-ARPES

Other Facilities: SSRL; NSRL