Layer-controlled evolution of electron state in the silicene intercalation compound SrSi₂

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Silicene, a graphene analog, offers promising electronic properties but suffers from high reactivity.
• Stoichiometric compounds like MSi2, formed with active metals, can stabilize silicene.
• These MSi2 compounds are candidate topological semimetals, enabling studies of layer-dependent electronic structures.

Purpose of the Study:

• To investigate the layer-dependent electronic properties of strontium silicide (SrSi2), a stabilized silicene compound.
• To explore the evolution of electronic states from bulk to single-monolayer SrSi2.
• To understand the stability of the chiral state and localization phenomena in few-layer silicene.

Main Methods:

• Synthesis of SrSi2 films on silicon, ranging from bulk to monolayer.
• Characterization using electron diffraction, X-ray diffraction, and high-resolution electron microscopy.
• Transport measurements to analyze electronic behavior, including chiral anomaly and localization.

Main Results:

• Monolayer number in SrSi2 dictates the electronic state.
• Transport measurements show a transition from chiral anomaly in bulk to weak localization in 3-monolayer films.
• 3D and 2D strong localization observed in 2- and 1-monolayer films, respectively.

Conclusions:

• The electronic state of SrSi2 is tunable by controlling the number of monolayers.
• The study defines the stability range of the chiral state for potential applications.
• Insights into localization phenomena in few-layer silicene systems are provided.