Presentation Title

Achieving and controlling electron tunneling in a scanning tunneling microscope

Faculty Mentor

Paul Dixon

Start Date

18-11-2017 12:30 PM

End Date

18-11-2017 1:30 PM

Location

BSC-Ursa Minor 118

Session

Poster 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Mandy Ledford

Francisco Caballero

Daniel Gagnon

Mentor: Paul K. Dixon

Achieving and controlling electron tunneling in a scanning tunneling microscope

In this poster, we will present a scanning tunneling microscope (STM) design that has been constrained by cost; the ultimate objective is a STM with a materials cost significantly below that of low-end commercial models. To accomplish this, we used a variety of novel approaches to the various problems that arise in implementing a STM. A “magnetic cross”, assembled from rare earth magnets and hand-wound solenoids, is used to achieve horizontal actuation. Vertical actuation is achieved through the use of a low cost piezoelectric stack, and a motor controlled platform for close approach. In this poster, we will focus on our techniques for acquiring and controlling electron tunneling. The close approach system is pivotal to the project because it allows for the acquisition of tunneling current without crashing the STM’s tip. Integration of the piezo electric stack, the motor controlled platform and LabVIEW software has made this possible. Once electron tunneling has been obtained, it must be sustained for a substantial period of time for successful scanning. Using a PID algorithm written in LabVIEW to control the movement of the piezoelectric stack, we have been able to sustain tunneling for extended periods. Our results show that, through the use of low cost materials and simple construction techniques, sustained electron tunneling can be achieved.

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Nov 18th, 12:30 PM Nov 18th, 1:30 PM

Achieving and controlling electron tunneling in a scanning tunneling microscope

BSC-Ursa Minor 118

Mandy Ledford

Francisco Caballero

Daniel Gagnon

Mentor: Paul K. Dixon

Achieving and controlling electron tunneling in a scanning tunneling microscope

In this poster, we will present a scanning tunneling microscope (STM) design that has been constrained by cost; the ultimate objective is a STM with a materials cost significantly below that of low-end commercial models. To accomplish this, we used a variety of novel approaches to the various problems that arise in implementing a STM. A “magnetic cross”, assembled from rare earth magnets and hand-wound solenoids, is used to achieve horizontal actuation. Vertical actuation is achieved through the use of a low cost piezoelectric stack, and a motor controlled platform for close approach. In this poster, we will focus on our techniques for acquiring and controlling electron tunneling. The close approach system is pivotal to the project because it allows for the acquisition of tunneling current without crashing the STM’s tip. Integration of the piezo electric stack, the motor controlled platform and LabVIEW software has made this possible. Once electron tunneling has been obtained, it must be sustained for a substantial period of time for successful scanning. Using a PID algorithm written in LabVIEW to control the movement of the piezoelectric stack, we have been able to sustain tunneling for extended periods. Our results show that, through the use of low cost materials and simple construction techniques, sustained electron tunneling can be achieved.