Tunable Hetero-Intercalated 2D Superlattice for Frustrated Kondo Triangles.

Abstract

With the successes of van der Waals heterostructures in unveiling exotic quantum states and enabling applications, direct fabrication of 2D superlattices beyond bulk limits is appealing. We realize an unprecedented 2D Kondo superlattice, Ta-NbS₂, consisting of two coupled metallic 1H-NbS₂ monolayers intercalated with growth-controlled periodic Ta sublattices. One-step CVD enables tunable periodicities, yielding three Ta-moment motifs: bulk-like simple triangular geometry of <math xmlns="http://www.w3.org/1998/Math/MathML"> <semantics> <mrow><msqrt><mn>3</mn></msqrt> <mspace></mspace></mrow> <annotation>$\sqrt 3\! $</annotation></semantics> </math> a× <math xmlns="http://www.w3.org/1998/Math/MathML"> <semantics> <mrow><msqrt><mn>3</mn></msqrt> <mspace></mspace></mrow> <annotation>$\sqrt 3\! $</annotation></semantics> </math> a (Type I), 2D spin-frustrated 4a×4a (Type II), and 2D saturated <math xmlns="http://www.w3.org/1998/Math/MathML"> <semantics><mrow><mn>3</mn> <msqrt><mn>3</mn></msqrt> <mspace></mspace></mrow> <annotation>$3\sqrt 3\! $</annotation></semantics> </math> a× <math xmlns="http://www.w3.org/1998/Math/MathML"> <semantics><mrow><mn>3</mn> <msqrt><mn>3</mn></msqrt> <mspace></mspace></mrow> <annotation>$3\sqrt 3\! $</annotation></semantics> </math> a (Type III). Beyond the logarithmic resistance upturn at Kondo temperature (T_K), we observe anomalous Hall effect evolution from single-impurity to coherent Kondo regimes, reflecting collective Ta-Kondo sublattice interactions. Carrier density modulation tunes the balance between Kondo screening and RKKY interactions, establishing 2D bilayer Ta-NbS₂ as an ultra-tunable 2D Kondo superlattice for correlated quantum phenomena, with potential applications in spintronics and quantum devices.