Coulomb drag in graphene/hBN/graphene moiré heterostructures
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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866912092399861760 |
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| author | Wang, Yueyang Xue, Hongxia Wang, Xiong Watanabe, Kenji Taniguchi, Takashi Ki, Dong-Keun |
| author_facet | Wang, Yueyang Xue, Hongxia Wang, Xiong Watanabe, Kenji Taniguchi, Takashi Ki, Dong-Keun |
| contents | We report on the observation of Coulomb drag between graphene-hexagonal boron nitride (hBN) moiré heterostructure with a moiré wavelength of $\sim$14 nm and an intrinsic graphene with a lattice constant of $\sim$0.25 nm. By tuning carrier densities of each graphene layer independently, we find that the charge carriers in moiré mini-bands, i.e., near the satellite Dirac point (sDP), can be coupled with the massless Fermions near the original Dirac point (oDP), strongly enough to generate a finite drag resistivity. At high temperature ($T$) and large density ($n$), the drag resistivities near both oDP and sDP follow a typical $n^{-α}$ ($α=1.3\sim1.7$) and $T^2$ power law dependence as expected for the momentum transfer process and it also satisfies the layer reciprocity. In contrast, at low $T$, the layer reciprocity is broken in both oDP-oDP and sDP-oDP coupled regions that suggest dominant energy drag. Furthermore, quantitatively, the drag resistivities near sDPs are smaller than those near oDP and they deviate from $T^2$ dependence below $\sim$100 K. These results suggest that the coupling between the carriers in moiré mini-bands and those in original Dirac bands may not be of a simple Fermi liquid nature. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2405_20393 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Coulomb drag in graphene/hBN/graphene moiré heterostructures Wang, Yueyang Xue, Hongxia Wang, Xiong Watanabe, Kenji Taniguchi, Takashi Ki, Dong-Keun Mesoscale and Nanoscale Physics We report on the observation of Coulomb drag between graphene-hexagonal boron nitride (hBN) moiré heterostructure with a moiré wavelength of $\sim$14 nm and an intrinsic graphene with a lattice constant of $\sim$0.25 nm. By tuning carrier densities of each graphene layer independently, we find that the charge carriers in moiré mini-bands, i.e., near the satellite Dirac point (sDP), can be coupled with the massless Fermions near the original Dirac point (oDP), strongly enough to generate a finite drag resistivity. At high temperature ($T$) and large density ($n$), the drag resistivities near both oDP and sDP follow a typical $n^{-α}$ ($α=1.3\sim1.7$) and $T^2$ power law dependence as expected for the momentum transfer process and it also satisfies the layer reciprocity. In contrast, at low $T$, the layer reciprocity is broken in both oDP-oDP and sDP-oDP coupled regions that suggest dominant energy drag. Furthermore, quantitatively, the drag resistivities near sDPs are smaller than those near oDP and they deviate from $T^2$ dependence below $\sim$100 K. These results suggest that the coupling between the carriers in moiré mini-bands and those in original Dirac bands may not be of a simple Fermi liquid nature. |
| title | Coulomb drag in graphene/hBN/graphene moiré heterostructures |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2405.20393 |