Anomalous charge density wave in altermagnetism

TL;DR

This paper predicts and characterizes an anomalous charge density wave in two-dimensional altermagnetic WO, revealing a new stabilization mechanism driven by occupied states away from the Fermi level and highlighting the role of altermagnetism.

Contribution

It introduces the concept of anomalous charge density wave in altermagnetic materials, supported by symmetry analysis and first-principles calculations, a novel phenomenon in condensed matter physics.

Findings

Anomalous charge density wave is stabilized by states far below the Fermi level.

It increases the density of states near the Fermi level, enhancing metallicity.

Altermagnetism is crucial for stabilizing the anomalous charge density wave.

Abstract

Exploring the intricate interplay between magnetism and charge density waves has long been a fundamental pursuit at the forefront of condensed matter research. In this letter, based on symmetry analysis and first-principles calculations, we propose for the first time that anomalous charge density wave can be realized in two-dimensional altermagnetic WO. The anomalous charge density wave is characterized by three key features: (i) Unlike conventional charge density wave, whose stabilization is driven by the opening of a gap near the Fermi level, the anomalous charge density wave is stabilized by the occupied states with energies shifting lower far away from the Fermi level; (ii) the anomalous charge density wave increases the density of states near the Fermi level and then enhances-rather than diminishes-the metallicity of materials; (iii) altermagnetism plays a crucial role in stabilizing anomalous charge density wave. Thus, our work offers a pathway for exploring both the realization and the underlying mechanisms of anomalous charge density waves in magnetic systems.