Robust Surface States and Coherence Phenomena in Magnetically Alloyed SmB_{6}

Area of Science:

• Condensed Matter Physics
• Materials Science
• Topological Materials

Background:

• Samarium hexaboride (SmB6) is a prime candidate for topological Kondo insulator (TKI) states.
• TKIs exhibit insulating gaps with protected topological surface states.
• Kondo coherence is theorized to drive the insulating gap in SmB6.

Purpose of the Study:

• Investigate the electronic properties of magnetically alloyed SmB6 (Sm1-xMxB6, M=Ce, Eu).
• Determine the persistence of topological surface states under magnetic alloying.
• Understand the relationship between bulk electronic structure and surface phenomena.

Main Methods:

• Angle-resolved photoemission spectroscopy (ARPES) for surface and bulk electronic structure.
• Characterization of magnetic and structural properties of alloyed samples.
• Analysis of band structures and electronic gaps.

Main Results:

• Topologically nontrivial band structures persist in Sm1-xMxB6 with up to 30% substitution.
• Alloying with Ce and Eu maintains the characteristic electronic properties of SmB6.
• An antiferromagnetic ground state was observed for Eu-doped samples.
• Surface state emergence is linked to a direct Kondo gap, while transport is governed by an indirect gap.

Conclusions:

• Magnetic alloying does not destroy the topological nature of SmB6.
• A hierarchy of energy scales governs the electronic properties, distinguishing surface and bulk behavior.
• SmB6 remains a promising platform for exploring topological quantum phenomena.