Inherited itinerant ferromagnetism on the polar surface in Na-intercalated antiferromagnet NaCrTe2.

Manipulating magnetism in two-dimensional (2D) van der Waals (vdW) materials arouses considerable and ongoing interest in fundamental physics and potential applications in next-generation spintronics. Here, we have investigated the underlying electronic structures of bulk vdW magnets CrTe2 and NaCrTe2, by carrying out high-resolution angle-resolved photoemission spectroscopy (ARPES) studies and first-principles calculations. In CrTe2, strong out-of-plane band dispersions and metallic Fermi surface are observed, accompanied by temperature-dependent ferromagnetic (FM) energy gain behavior which directly confirms its itinerant origin. In sharp contrast, NaCrTe2 turns into an A-type antiferromagnetic (AFM) semiconductor in calculations and transport measurements. Remarkably, robust ferromagnetisminherited from CrTe2 is distinguished on the polar surface of AFM NaCrTe2. Our results not only reveal the itinerant FM mechanism of CrTe2, but alsodemonstrate that chemical doping is a powerful tuning knob to manipulate the properties of 2D magnetic material. Moreover, we establish NaCrTe2 as an excellent AFM semiconductor platform with robust surface ferromagnetism, which is promising in practical applications. .