Interaction-Driven Surface Chern Insulator in Nodal Line Semimetals

Area of Science:

• Condensed Matter Physics
• Topological Materials

Background:

• Nodal line semimetals feature unique bulk-band crossings.
• These crossings create nearly flat drumhead-like surface states (DSS).
• DSS are promising for studying interaction-induced emergent phenomena.

Purpose of the Study:

• Investigate the impact of electronic interactions on DSS in nodal line semimetals.
• Determine if these interactions can lead to novel topological phases.
• Explore the potential for realizing dissipationless electron transport.

Main Methods:

• Theoretical analysis of electronic interactions within DSS.
• Inclusion of spin-orbit coupling effects.
• Investigation of topological charge and Chern number in surface states.

Main Results:

• Electronic interactions drive a Stoner ferromagnetic instability in DSS, distinct from the bulk.
• Combined with spin-orbit coupling, this instability transforms DSS into a 2D Chern insulator.
• Each DSS segment possesses a half-integer topological charge, leading to a net Chern number of C=-1 for systems with two DSS segments.
• The resulting topological state is robust against chiral-symmetry breaking.

Conclusions:

• Nodal line semimetals serve as a viable platform for realizing surface Chern insulators.
• Exploiting enhanced interaction effects in DSS can lead to dissipationless electron transport.
• This work opens avenues for novel topological quantum devices.