Long- versus Short-Range Scattering in Doped Epitaxial Graphene.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Surface Science

Background:

• Tuning graphene's electronic properties via adatom deposition is crucial for novel electronic devices.
• Adatom deposition inevitably introduces disorder, affecting fundamental electronic and electrodynamic properties.
• Understanding the nature of scattering introduced by adatoms is key to controlling graphene's behavior.

Purpose of the Study:

• To investigate the evolution of disorder in graphene induced by thallium adatom deposition.
• To probe the effect of thallium adatoms on graphene's electronic structure and quasiparticle excitations.
• To quantify the scattering potential introduced by charged thallium adatoms.

Main Methods:

• Utilized angle-resolved photoemission spectroscopy (ARPES) to study graphene.
• Analyzed photoemission spectral functions to identify signatures of quasiparticle scattering.
• Employed a self-energy model to characterize the scattering potential.

Main Results:

• Thallium adatoms were identified as efficient short-range scattering centers, despite being charged.
• Extracted a short-range scattering potential (δ-like) of -3.2 ± 1 eV.
• Demonstrated that isolated charged scattering centers contribute significantly to both short-range and long-range (Coulomb) scattering.

Conclusions:

• Charged adatoms can act as effective short-range scatterers, not solely long-range Coulomb scatterers.
• Thallium adatoms on graphene exhibit nearly equal contributions from short-range and Coulomb scattering mechanisms.
• This finding provides crucial insights into disorder engineering in 2D materials.