标题： 掺杂无序金属的晶体绝缘体中的赝能隙 显示英文标题

标题： Pseudogap in a crystalline insulator doped by disordered metals

摘要： 理解电子在晶体固体中行为的关键是能带结构，它将电子波的能量与其波数(k)联系起来。即使在只有短程有序的物质相（液体或非晶固体）中，电子波的相干部分仍然具有能带结构。液态金属的能带结构理论模型早在50多年前就已提出，但迄今为止，由共振散射引起的能带结构重整化和赝隙仍未被观察到。在这里，我们报告在晶体绝缘体（黑磷）与无序掺杂剂（碱金属）界面处观察到这种不寻常的能带结构。我们发现自由电子的传统抛物线形能带结构在零k处向回弯曲，并从费米能级开始有30-240 meV的赝隙。这是由共振散射引起的k重整化，导致在碱金属离子的散射势中形成准束缚态。通过不同种类的碱金属（Na、K、Rb和Cs）调节该势的深度，可以对p波和d波共振的赝隙进行分类。我们的结果可能为各种晶体绝缘体被无序掺杂剂掺杂后的令人困惑的谱提供了线索，例如铜氧化物中的瀑布形色散。 显示英文摘要

摘要： A key to understand how electrons behave in crystalline solids is the band structure that connects the energy of electron waves to their wavenumber (k). Even in the phase of matter with only short-range order (liquid or amorphous solid), the coherent part of electron waves still possesses a band structure. Theoretical models for the band structure of liquid metals were formulated more than 5 decades ago, but thus far, bandstructure renormalization and pseudogap induced by resonance scattering have remained unobserved. Here, we report the observation of this unusual band structure at the interface of a crystalline insulator (black phosphorus) and disordered dopants (alkali metals). We find that a conventional parabolic band structure of free electrons bends back towards zero k with the pseudogap of 30-240 meV from the Fermi level. This is k renormalization caused by resonance scattering that leads to the formation of quasi-bound states in the scattering potential of alkali-metal ions. The depth of this potential tuned by different kinds of alkali metal (Na, K, Rb, and Cs) allows to classify the pseudogap of p-wave and d-wave resonance. Our results may provide a clue to the puzzling spectrum of various crystalline insulators doped by disordered dopants, such as the waterfall dispersion in cuprates.