Large ferromagnetic-like band splitting in ultrathin ${\mathrm{SmC}}_6$ films

Abstract

Two-dimensional (2D) magnetic materials provide a unique platform for exploring quantum phases from magnetic order in reduced dimensions. While there have been extensive studies on 2D magnetic materials based on 3$d$ electrons, experimental studies on 4$f$-electron counterparts are far fewer, particularly on their electronic structure. In this study, we report the successful synthesis of ultrathin ${\mathrm{SmC}}_6$ films using molecular beam epitaxy. Utilizing in situ angle-resolved photoemission spectroscopy (ARPES), we uncover a large band splitting in the valence bands, which we attribute to the ferromagnetic order driven by exchange couplings between Sm 4$f$ moments and conduction electrons. Despite the small magnetic moment of Sm, the observed splitting is comparable to those of Eu- and Gd-based systems with much larger local moments. Interestingly, the surface state also exhibits splitting with similar magnitude and can be eliminated by overannealing, while the valence bands with ferromagnetic-like splittings remain robust. Our work provides spectroscopic insight to understand the electronic origin of magnetic order in Sm-based compounds. Our study also offers a platform to study 2D magnetic materials based on 4$f$ electrons.

arXiv comment8 pages, 5 figures

References in corpus (15)

• Layer-dependent Ferromagnetism in a van der Waals Crystal down to the Monolayer Limit
• Discovery of intrinsic ferromagnetism in 2D van der Waals crystals
• Gate-tunable Room-temperature Ferromagnetism in Two-dimensional Fe${}_3$GeTe${}_2$
• Electrical Control of 2D Magnetism in Bilayer CrI3
• Topological Kondo Insulators
• Interfacial mode coupling as the origin of the enhancement of Tc in FeSe films on SrTiO3
• Altermagnetism: Exploring New Frontiers in Magnetism and Spintronics
• Surface electronic structure of the topological Kondo insulator candidate correlated electron system SmB6
• Observation of in-gap surface states in the Kondo insulator SmB6 by photoemission
• From Stoner to Local Moment Magnetism in Atomically Thin Cr2Te3
• Exotic Kondo crossover in a wide temperature region in the topological Kondo insulator SmB6 revealed by high-resolution ARPES
• Strong ferromagnetism at the surface of an antiferromagnet caused by buried magnetic moments
• SmB6 Photoemission: Past and Present
• Topological properties and the dynamical crossover from mixed-valence to Kondo-lattice behavior in golden phase of SmS
• Electronic band reconstruction across the insulator-metal transition in colossal magnetoresistive EuCd2P2