Exploring In on InAs(111)A as a platform for quantum simulation

Abstract

Artificial lattices are of great interest for simulation of complex quantum systems. Rearranging CO molecules on Cu(111) has shown to be a very reliable method to construct them but energy broadening in the measurements posed a problem. We expect to solve this by using a different electronic platform: we are using the scanning tunneling microscope to manipulate In adatoms on an InAs(111)A-(2 x 2) surface. Samples grown using the Liquid Encapsulated Czochralski (LEC) technique with a top layer grown by molecular-beam epitaxy (MBE) were shown to exhibit less defects and are therefore more suitable for this experiment than LEC-grown samples without an MBE-grown layer. To increase the amount of adatoms for manipulation, In was deposited from a crucible onto the sample by heating the crucible via electron bombardment. The kinetic energy of the electrons plays an important role: 1 keV kinetic energy resulted in single In atoms on the surface, while 2 keV kinetic energy resulted in small clusters of In atoms. Vertical manipulation of In adatoms was performed while I (z ) traces were recorded. Individual In adatoms were picked up from and deposited onto the substrate with atomic precision. Challenges lie in finding out when and why holes in the surface are made when picking up an atom and how to prevent depositing clusters of In atoms. We constructed an In10 and an In6 chain using vertical manipulation. The lowest energy state of the In6 chain is reported to be located at -0.131 V. We did not detect a clear signal of this particle-in-a-box like state. To do this, the vertical manipulation method should be further optimized and more artificial lattices should be assembled. Quantum simulators constructed in this manner promise to be of great value in the field of quantum computing.