A new alloy for Al-chalcogen system: AlSe surface alloy on Al (111)

TL;DR

This study characterizes the crystal structure and electronic properties of a novel AlSe surface alloy on Al (111), revealing unique electronic bands and potential for nanoelectronics interfaces.

Contribution

It provides the first detailed analysis of the AlSe surface alloy's structure and electronic behavior, highlighting its unique properties compared to other metal chalcogenides.

Findings

AlSe surface alloy has a hexagonal close-packed structure.

Two hole-like bands are located at about -2.2 eV, below the Fermi level.

AlSe alloy offers large-scale flatness and a wide band gap for interface applications.

Abstract

Metal chalcogenide is a promising material for studying novel underlying physical phenomena and nanoelectronics applications. Here, we systematically investigate the crystal structure and electronic properties of the AlSe surface alloy on Al (111) using scanning tunneling microscopy, angle-resolved photoelectron spectrometer, and first-principle calculations. We reveal that the AlSe surface alloy possesses a hexagonal closed-packed structure. The AlSe surface alloy comprises two atomic sublayers (Se sublayer and Al sublayer) with 1.16 A along the z direction. The dispersion shows two hole-like bands for AlSe surface alloy located at about -2.2 eV, far below the Fermi level, which is sharply different from other metal chalcogenide and binary alloys. These two bands mainly derive from the in-plane orbital of AlSe (px and py). These results provide implications for related Al-chalcogen interface. Meanwhile, AlSe alloy have an advantage of large-scale atomic flatness and a wide band gap near the Fermi level in serving as an interface for two-dimensional materials.