Probing Electronic States at Endotaxial 2D Heterostructures

Endotaxial 2D heterostructures have recently emerged as promising candidates for the achievement of novel quantum states for classical and quantum computing. Of particular interest is the achievement of ultra-clean defect-free 2D materials within a bulk. Examples include chemically-homogeneous sandwiches of octahedral polytypes within the prismatic polytypes of TaS2 and MoSe2 (“polytype heterostructures”), as well as in van der Waals superlattices in which single or multiple 2D Bi2Te3 or Sb2Te3 layers are protected by Bi- or Sb-layers. In this talk, we present scanning tunneling spectroscopy and quasi-particle interference mapping of both endotaxial polytype heterostructures and van der Waals superlattices, emphasize the role of point defects on nucleation and propagation of endotaxial layers as well as the possibility of hosting topologically protected states along certain line defects in the van der Waals superlattices. <br/><i>This work is supported in part by </i><i>the Air Force Office of Scientific Research through the Multidisciplinary University Research Initiative, Award No. FA9550-23-1-0334 and the National Science Foundation through the Materials Research Science and Engineering Center at the University of Michigan, Award No. DMR-2309029.</i>