Evolving Devil's staircase magnetization from tunable charge density waves in nonsymmorphic Dirac semimetals

TL;DR

This paper demonstrates how tuning electron count in a square-net topological semimetal induces charge density waves and complex magnetic states, revealing a Devil's staircase magnetization pattern and coupling between charge order and magnetism.

Contribution

It introduces a method to control topological and magnetic phases in CeSbTe via electron filling, linking charge density waves with complex magnetic phenomena.

Findings

Charge density waves evolve with electron filling.

Observation of fractionally quantized magnetization plateaus.

Creation of a robust non-symmorphic Dirac semimetal.

Abstract

While several magnetic topological semimetals have been discovered in recent years, their band structures are far from ideal, often obscured by trivial bands at the Fermi energy. Square-net materials with clean, linearly dispersing bands show potential to circumvent this issue. CeSbTe, a square-net material, features multiple magnetic field-controllable topological phases. Here, it is shown that in this material, even higher degrees of tunability can be achieved by changing the electron count at the square-net motif. Increased electron filling results in structural distortion and formation of charge density waves (CDWs). The modulation wave-vector evolves continuously leading to a region of multiple discrete CDWs and a corresponding complex "Devil's staircase" magnetic ground state. A series of fractionally quantized magnetization plateaus are observed, which implies direct coupling between CDW and a collective spin-excitation. It is further shown that the CDW creates a robust idealized non-symmorphic Dirac semimetal, thus providing access to topological systems with rich magnetism.