title: Micro-metric electronic patterning of a topological band structure using a photon beam.
abstract: In an ideal 3D topological insulator (TI), the bulk is insulating and the surface conducting due to the existence of metallic states that are localized on the surface; these are the topological surface states. Quaternary Bi-based compounds of Bi(2-x)Sb(x)Te(3-y)Se(y) with finely-tuned bulk stoichiometries are good candidates for realizing ideal 3D TI behavior due to their bulk insulating character. However, despite its insulating bulk in transport experiments, the surface region of Bi(2-x)Sb(x)Te(3-y)Se(y) crystals cleaved in ultrahigh vacuum also exhibits occupied states originating from the bulk conduction band. This is due to adsorbate-induced downward band-bending, a phenomenon known from other Bi-based 3D TIs. Here we show, using angle-resolved photoemission, how an EUV light beam of moderate flux can be used to exclude these topologically trivial states from the Fermi level of Bi1.46Sb0.54Te1.7Se1.3 single crystals, thereby re-establishing the purely topological character of the low lying electronic states of the system. We furthermore prove that this process is highly local in nature in this bulk-insulating TI, and are thus able to imprint structures in the spatial energy landscape at the surface. We illustrate this by 'writing' micron-sized letters in the Dirac point energy of the system.
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Frantzeskakis
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: N
authors.initials: N
authors.lastname: De Jong
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: Zwartsenberg
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: Y K
authors.initials: YK
authors.lastname: Huang
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: T V
authors.initials: TV
authors.lastname: Bay
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Pronk
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Van Heumen
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Wu
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: Y
authors.initials: Y
authors.lastname: Pan
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.|SwissFEL, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Radovic
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
authors.forename: N C
authors.initials: NC
authors.lastname: Plumb
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
authors.forename: N
authors.initials: N
authors.lastname: Xu
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Shi
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: De Visser
authors.affiliation: Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: M S
authors.initials: MS
authors.lastname: Golden