报告题目：A novel artificial condensed matter lattice and a new platform for one-dimensional topological phases

报 告 人：Ilya Belopolski，Princeton University

报告时间：6月13日，周二，上午10:30

报告地点：物理系三楼报告厅

报告摘要：We are always searching for new ways to manipulate and engineer materials. To change the properties of a crystal, we can use strategies like chemical doping, applying pressure, changing the temperature or varying the thickness of a film. We also have clever ways to engineer band structures from the ground up in cold-atom optical lattices or photonic crystals. In this talk, I will demonstrate a new scheme to engineer band structures, using topological insulators. We use molecular beam epitaxy (MBE) to stack thin films of trivial and topological insulators in an alternating pattern to form a multilayer heterostructure. Each interface hosts topological interface states. By making each layer < 7nm thick, we allow quantum tunneling between nearby interfaces. in this way, we form an emergent, tunable superlattice band structure where each interface acts as a lattice site and each topological interface state acts as an atomic orbital. after introducing the basic concept, i will present data from angle-resolved photoemission spectroscopy (arpes) demonstrating an emergent electronic band structure. i will also discuss how we might use this scheme to realize novel topological invariants in both 3d and 1d, as well as other neat applications. reference: belopolski et al., sci. adv., e1501692 (2017).