Abstract
The proximity-effect, a phenomenon whereby materials in close contact appropriate each other’s electronic-properties, is widely used in nano-scale devices to induce electron-correlations at heterostructure interfaces. Commonly observed proximity-induced correlation-effects include superconductivity, magnetism, and spin-orbit interactions. Thus far, however, proximity induced charge density waves (CDW) have not been rigorously explored, primarily because of screening in 3D metals and defect scattering at interfaces. Here, we report the observation of a CDW proximity effect between graphene and the commensurate CDW in 1T-TaS2 (henceforth called TaS2 for brevity). Using scanning tunneling microscopy (STM) and spectroscopy (STS) together with theoretical modeling to probe the interface between graphene and a TaS2 crystal, we demonstrate the existence of a proximity induced CDW within graphene. Furthermore, we observe that graphene modifies the band structure at the surface of TaS2, by providing mid-gap carriers and reducing the strength of electron correlations there. We show that the mechanism underlying the proximity induced CDW is well-described by short-range exchange interactions that are distinctly different from previously observed proximity effects.
*NT and EYA acknowledge support from the Department of Energy grant DOE-FG02-99ER45742 and the Gordon and Betty Moore Foundation EPiQS initiative grant GBMF9453; MAA was supported by the National Science Foundation grant EFRI 1433307; GL was supported by Rutgers University; C.-H. C. was supported by MOST (Grant NO.: 107-2112-M-009-010-MY3, 110-2112-M-A49-018-MY3) and the NCTS of Taiwan, R.O.C., J.H.T acknowledges support from the Ministry of Science and Technology, Taiwan under grant: MOST 109-2112-M-007 -034 -MY3, and from NCHC, CINC-NTU, AS-iMATE-109-13, and CQT-NTHU-MOE, Taiwan.
