Metal-Insulator Transition and Emergent Gapped Phase in the Surface-Doped 2D Semiconductor 2 H − MoTe 2

作者：Tingting Han, L. Chen, Cong Cai, Zhengguo Wang, Y. D. Wang, Z. M. Xin, Yan Zhang · 发表于：Physical Review Letters · 年份：2021 · DOI：10.1103/physrevlett.126.106602 · 被引用次数：21 · 研究领域：2D Materials and Applications、Electronic and Structural Properties of Oxides、Advanced Thermoelectric Materials and Devices

Artificially created two-dimensional (2D) interfaces or structures are ideal for seeking exotic phase transitions due to their highly tunable carrier density and interfacially enhanced many-body interactions. Here, we report the discovery of a metal-insulator transition (MIT) and an emergent gapped phase in the metal-semiconductor interface that is created in 2H-MoTe_{2} via alkali-metal deposition. Using angle-resolved photoemission spectroscopy, we found that the electron-phonon coupling is strong at the interface as characterized by a clear observation of replica shake-off bands. Such strong electron-phonon coupling interplays with disorder scattering, leading to an Anderson localization of polarons which could explain the MIT. The domelike emergent gapped phase could then be attributed to a polaron extended state or phonon-mediated superconductivity. Our results demonstrate the capability of alkali-metal deposition as an effective method to enhance the many-body interactions in 2D semiconductors. The surface-doped 2H-MoTe_{2} is a promising candidate for realizing polaronic insulator and high-T_{c} superconductivity.