Department of Physics, Columbia University, New York, New York 10027, USA.
Department of Applied Physics and Applied Math, Columbia University, New York, New York 10027, USA.
Phys Rev Lett. 2015 Jan 23;114(3):037001. doi: 10.1103/PhysRevLett.114.037001. Epub 2015 Jan 21.
We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe2 that we measure by scanning tunneling spectroscopic imaging. We show, from the momentum and energy dependence of the quasiparticle interference, that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe2. We demonstrate that, by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wave vector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology and the interactions. In 2H-NbSe2, we use this combination to confirm that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the charge density wave ordering wave vector.
我们表明，少量有意引入的缺陷可用作光谱工具，以放大我们通过扫描隧道光谱成像测量的 2H-NbSe2 中的准粒子干涉。我们从准粒子干涉的动量和能量依赖性表明，在 2H-NbSe2 中，费米面嵌套对电荷密度波形成没有影响。我们证明，通过将准粒子干涉数据与角分辨光电子能谱测量中准粒子能带结构的其他知识相结合，人们可以提取重要电子散射过程的波矢和能量依赖性，从而获得有关费米物理学和相互作用的直接信息。在 2H-NbSe2 中，我们使用这种组合来证实，重要的近费米面电子物理学主要由准粒子与软模声子在不同于电荷密度波有序波矢的波矢处的耦合所主导。
