# Electronic band structure of ultimately thin silicon oxide on Ru(0001)

## TL;DR

This study elucidates the atomic structure and electronic properties of an epitaxially grown, ultra-thin silicon oxide on Ru(0001), revealing unique sub-lattice arrangements and electronic bands including a Dirac cone, with implications for catalysis and 2D materials.

## Contribution

It provides the first detailed atomic and electronic characterization of crystalline silicon oxide on Ru(0001), highlighting its sub-lattice structure and electronic bands, including Dirac features.

## Key findings

- Identification of two sub-lattices in the oxide structure.
- Discovery of four electronic bands, including a Dirac cone.
- Hybridized states between oxide and metal observed.

## Abstract

Silicon oxide can be formed in a crystalline form, when prepared on a metallic substrate. It is a candidate support catalyst and possibly the ultimately-thin version of a dielectric host material for two-dimensional materials (2D) and heterostructures. We determine the atomic structure and chemical bonding of the ultimately thin version of the oxide, epitaxially grown on Ru(0001). In particular, we establish the existence of two sub-lattices defined by metal-oxygen-silicon bridges involving inequivalent substrate sites. We further discover four electronic bands below Fermi level, at high binding energies, two of them forming a Dirac cone at K point, and two others forming semi-flat bands. While the latter two correspond to hybridized states between the oxide and the metal, the former relate to the topmost silicon-oxygen plane, which is not directly coupled to the substrate. Our analysis is based on high resolution X-ray photoelectron spectroscopy, angle-resolved photoemission spectroscopy, scanning tunneling microscopy, and density functional theory calculations.