Creating Tunable Quantum Corrals on a Rashba Surface Alloy

Abstract

Artificial lattices derived from assembled atoms on a surface using scanning tunneling microscopy present a platform to create matter with tailored electronic, magnetic, and topological properties. However, artificial lattice studies to date have focused exclusively on surfaces with weak spin–orbit coupling. Here, we illustrate the creation and characterization of quantum corrals from iron atoms on the prototypical Rashba surface alloy BiCu 2 , using low-temperature scanning tunneling microscopy and spectroscopy. We observe very complex interference patterns that result from the interplay of the size of the confinement potential, the intricate multiband scattering, and hexagonal warping from the underlying band structure. On the basis of a particle-in-a-box model that accounts for the observed multiband scattering, we qualitatively link the resultant confined wave functions with the contributions of the various scattering channels. On the basis of these results, we studied the coupling of two quantum corrals and the effect of the underlying warping toward the creation of artificial dimer states. This platform may provide a perspective toward the creation of correlated artificial lattices with nontrivial topology.

Phase Transformation-Induced Quantum Dot States on the Bi/Si(111) Surface

“…Trivial errors in theoretical peak positions might be attributed to atomic vibrations at room temperature and the simplifications of the assumed potential, which are acceptable here for qualitative eigenwave analysis. Similar features have also been observed in STS maps for the InAsP/InP QDs, graphene QDs, and BiCu2 quantum corrals …”

“…Similar features have also been observed in STS maps for the InAsP/InP QDs, 42 graphene QDs, 43 and BiCu2 quantum corrals. 44 Additional QD systems varying from 7.7 to 3.5 nm are shown in Figure S3 accompanied by their STS results, from which QDSs peculiar to β-phase Bi islands can be recognized. QD islands are formed during β-to-α phase transformation triggered by thermal annealing at 700 K. The dot size is determined by the initial β surface area and the sample annealing time, as detailed in the following paragraphs.…”

Formation of an Extended Quantum Dot Array Driven and Autoprotected by an Atom-Thick h-BN Layer

“…Considering that h -BN is known to induce an upshift of the Cu(111) surface state by about 0.11 eV due to the weak interaction with the h -BN overlayer, , our observed onset (∼ −0.32 V) of the confined states fits well to the suggestion that Cu(111) surface state electrons are confined beneath the protecting h -BN. We state that the corrugated CuS reconstruction, defining the QD array, is the scatterer responsible for the confinement, analogous to traditional surface state scattering by steps, corrals ,,, and surface reconstructions . This is further assured by high-resolution STM images of previously studied CuS reconstructions on Cu(111), where clear standing wave patterns were displayed. , …”

“…Employing the former, quantum confinement in adatom corrals, , quantum mirage effects, artificial lattices promoting exotic properties, , and pseudologic gates could be realized and explored, expanding our fundamental understanding of quantum phenomena.…”

Quantum Materials and Devices at ACS Nano

“…Quantum materials and devices are now entering the regime where we can predict, synthesize, and image them, ushering in a world where we can engineer these devices atom-by-atom. In parallel, discoveries in quantum materials, characterized by the strongly quantum-mechanical nature of electrons and atoms, have revealed exotic properties that arise from strong electronic correlations, , including unconventional superconductors, topological insulators, Dirac and Weyl semimetals, spin liquids, and new phases of matter induced via light-matter interactions. , Part of my (P.N.) motivation for joining the ACS Nano team was to grow this intersection of nanoscience, chemistry, quantum materials, theory and computation, and quantum devices.…”