标题： 单层MoS$_2$中的非弹性隧穿进入多极子束缚态 显示英文标题

标题： Inelastic tunneling into multipolaronic bound states in single-layer MoS$_2$

摘要： 极化子是电子或空穴与晶格振动相互作用产生的准粒子。 尽管极化子在多个学科中已被广泛研究，但在二维晶体中对极化子的实验观察仍很少。 我们使用扫描隧道显微镜和谱学来测量非极性区边界声子与n型掺杂金属单层MoS$_2$中布洛赫电子耦合所产生的极化子束缚态的非弹性激发。 后者通过无接触化学掺杂保持化学纯净。 进入振动耦合的极化子态会导致费米能级两侧的微分电导中出现一系列等间距峰。 结合密度泛函（微扰）理论与一种最近开发的从头算电子-晶格下折叠技术，我们表明能量间隔源自在布里渊区边缘变平的纵向声学声子模式，并且该模式负责金属MoS$_2$中稳定多极化子的形成。 显示英文摘要

摘要： Polarons are quasiparticles that arise from the interaction of electrons or holes with lattice vibrations. Though polarons are well-studied across multiple disciplines, experimental observations of polarons in two-dimensional crystals are sparse. We use scanning tunneling microscopy and spectroscopy to measure inelastic excitations of polaronic bound states emerging from coupling of non-polar zone-boundary phonons to Bloch electrons in n-doped metallic single-layer MoS$_2$. The latter is kept chemically pristine via contactless chemical doping. Tunneling into the vibrationally coupled polaronic states leads to a series of evenly spaced peaks in the differential conductance on either side of the Fermi level. Combining density functional (perturbation) theory with a recently developed ab initio electron-lattice downfolding technique, we show that the energy spacing stems from the longitudinal-acoustic phonon mode that flattens at the Brillouin zone edge and is responsible for the formation of stable multipolarons in metallic MoS$_2$.