2 × 2 Charge Density Wave in Fe_0.33NbSe₂ Stabilized by Disordered Intercalation

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Emergent phenomena in quantum materials, such as charge density waves (CDWs), arise from the interplay between electronic and lattice properties.
• Understanding the roles of electron carriers and structural order is key to controlling material properties, but isolating these effects is challenging due to intertwined charge doping and structural periodicity.

Purpose of the Study:

• To investigate the mechanism stabilizing a 2x2 CDW in Fe-intercalated NbSe2.
• To demonstrate the role of disorder-induced charge doping in modulating lattice modulations and electronic structure.

Main Methods:

• Experimental observation of a 2x2 CDW in Fe0.33NbSe2 using techniques sensitive to electronic structure.
• Analysis of band and Fermi surface folding to confirm electronic structure reconstruction.

Main Results:

• A 2x2 CDW in Fe0.33NbSe2 was observed, stabilized by disordered Fe intercalation.
• Charge transfer from the intercalated Fe layer was identified as crucial for stabilizing the CDW modulation in NbSe2 layers.
• Evidence of electronic structure reconstruction was found through band and Fermi surface folding, with temperature-dependent spectral weight changes consistent with CDW behavior.

Conclusions:

• Disordered Fe intercalation effectively induces charge doping, stabilizing a 2x2 CDW in NbSe2.
• Electronic structure reconstruction accompanies the CDW transition, as evidenced by band folding.
• Disorder-induced charge doping presents a viable strategy for tuning the electronic properties of two-dimensional materials.