AVS 62nd International Symposium & Exhibition
    Novel Trends in Synchrotron and FEL-Based Analysis Focus Topic Monday Sessions
       Session SA-MoA

Paper SA-MoA2
Micro-metric Electronic Patterning of a Topological Band Structure using a Photon Beam

Monday, October 19, 2015, 2:40 pm, Room 112

Session: New Insights in Correlated Materials, Organic Materials and 2D Solids
Presenter: Nick de Jong, University of Amsterdam
Authors: N. de Jong, University of Amsterdam
E. Frantzeskakis, University of Amsterdam
B. Zwartsenberg, University of Amsterdam
Y. Huang, University of Amsterdam
B.V. Tran, University of Amsterdam
P. Pronk, University of Amsterdam
E. van Heumen, University of Amsterdam
D. Wu, University of Amsterdam
Y. Pan, University of Amsterdam
M. Radovic, Paul Scherrer Institute
N.C. Plumb, Paul Scherrer Institut
N. Xu, Paul Scherrer Institut
M. Shi, Paul Scherrer Institute
A. de Visser, University of Amsterdam
M.S. Golden, University of Amsterdam
Correspondent: Click to Email
We discuss a method of “writing” spatial micro-metric patterns in the electronic surface band structure of the topological insulator (TI) Bi1.46Sb0.54Te1.7Se1.3. Due to fine-tuning of the bulk stoichiometry this material is truly insulating, making it a promising candidate for applications where the special transport properties of the topological protected surfaces states are necessary. However despite the insulating character bulk in transport experiments, the spectroscopic fingerprint of Bi1.46Sb0.54Te1.7Se1.3 is not that of an insulator. Due to band bending, the conduction band is partly occupied at the surface of the material. We present a way to counteract the occupation of the conduction band in both global and local spatial scales. Namely, we make use of an extreme ultra violet photon beam with superband gap energy and a flux exceeding 1021 photons/(s m2) as a “writing tool”. This is a three-step process. First an area of approximately 500 mm x 500 mm is mapped out by angle resolved photoemission spectroscopy (ARPES), taking a spectrum of the topological surface state at each sample location. Secondly, we expose selected sample locations to a higher fluence photon beam. These locations form a pre-defined pattern. Finally, the first map of the area is then again by ARPES. In this way we are able to shift the electronic surface band structure and drive the bulk conduction band to the unoccupied part of the spectrum. This shift is observed to be very local and in our case is only limited by the size of the beam and not by the approach itself.