Researchers design a way to sketch quantum devices with focused electrons

PITTSBURGH – It has long been a dream to create new materials from the “top down” choosing which atoms go where they invent interesting buildings. A device devised by researchers from the Department of Physics and Astronomy allows them to “sketch” patterns of electricity into a programmed quantum material – lanthanum aluminate / strontium titanate or “LAO / STO”. Using this approach, they can create quantum devices with feature sizes that resemble the space between electrons, and even “sketch” artificial torches to transmit electricity, with very high precision.

To develop this capability, the researchers replaced the electron beam lithography instrument, which is typically used to create nanostructures by exposing a hardening face mask in a mask, allowing layers of material to be added or removed. Instead of operating the instrument at its normal value of 20,000 Volts, the researchers lowered it to just a few hundred volts, where the surface electrons could not filter their oxide material, and instead – not to resist – catalyzing a resurfacing surface that gives the LAO a good surface finish, and the locally driven LAO / STO interface. The electron conduction is 10,000 times faster at writing compared to lithography based on an atomic microscope, without losing spatial resolution or reproducibility. Furthermore, the authors showed that this method can program a LAO / STO interface when paired with other 2D layers such as graphene.

The team is led by Jeremy Levy, Distinguished Professor of Condensed Physics and director of the Quantum Institute of Pittsburgh, describing the approach in the paper, “Nanoscale Control of LaAIO3 / SrTiO3 Metal Insulator Transitions use of ultra-low voltage electron beam. lithography. “The paper was published in Applied Physics Letter on December 21st.

Dengyu Yang, a graduate student who developed the technique and is the lead author of the paper, compared it to “drawing a sketch on canvas with a pen.”

“In this case, the canvas is LAO / STO and the” pen “is a carrier of electrons. This powerful ability allows us to participate with more complex structures and wear the device from one side to two dimensions, “she said.

Yang and Levy said this discovery could have an impact in the areas of quantum transport and quantum simulation.

“We are very interested in using this method to create new families of two-dimensional electronics based on a series of artificial atoms written using this method. Our group recently published a paper in Science Advances highlighting the idea of ​​quantum simulation in one-dimensional devices, using the AFM method. This new EBL – based device will allow us to perform quantum simulation in two dimensions, “said Levy.

In addition to Yang and Levy, Pitt ‘s colleagues on the paper include research professor Patrick Irvin and graduate students Shan Hao, Qing Guo, Muqing Yu, Yang Hu, Associate Professor Jun Chen from Swanson School of Engineering. Additional links include the Department of Materials Science and Engineering at the University of Wisconsin-Madison and the Quantum Institute of Pittsburgh.

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