A faster microscope

Atoms are the fundamental building blocks of matter. Nowadays, it is possible to visualize these atoms individually using electron microscopes. These instruments use a technique known as spectroscopy to not only identify individual atoms but also observe their collective behavior and determine properties of the material they form – whether it is, for example, a superconducting metal or an insulator.

The project will expand the electron microscope toolbox with novel technology using light of the microwave wavelength. This enables ultrashort exposure times, on the order of a few tens of femtoseconds – a femtosecond being a billionth of a millionth of a second. These ultrashort exposure times can be used to study extremely fast processes occurring in materials, while maintaining the state-of-the-art precision of electron microscope imaging and spectroscopy.

The project will be carried out by a broad collaboration. It aims to implement and commercialize the patented technology in electron microscopes produced by ThermoFisher Scientific, with help from the electronics developed by TU/e spin-off Dr X works B.V. Van Heumen’s team at the University of Amsterdam will then use the new microscope to tackle two major outstanding scientific problems and demonstrate the capabilities of the new instrument.

Two outstanding problems

By introducing microwave cavities in the transmission electron microscope, the electron beam that it produces can be pulsed, resulting in electron bunches that are only 10 femtoseconds long. This eventually enables the researchers to study the real space movement of electrons and ionized atoms in materials on those timescales. The resulting stop-motion movies will be used to visualize switching in novel oxide based memristors: basic building blocks of low energy consumption memories that will help to reduce energy consumption in large scale computing facilities. In normal transistors, switching between on and off, or 1 and 0, occurs by applying a voltage that needs to be always kept. Memristors can be switched by a single voltage pulse and will stay in their new state forever. By imaging the switching processes in these memristor devices, the team hopes to unravel the origin of breakdown behaviour that currently limits the number of switching cycles. Solving this problem could help to further develop this technology.

The second outstanding scientific question involves a very fundamental question as to the origin of electron dynamics in high temperature superconductors – materials that can conduct electricity virtually without resistance. Efforts to understand the origin of the relatively high temperature below which so-called cuprate superconductors lose their resistance, has focused in recent years on understanding the properties of the metallic state at higher temperatures. While it is a mystery why the material loses all resistance at low temperature, the source of the resistance at high temperature turns out to be equally mysterious. The conventional theory describing the motion of electrons makes predictions for the temperature dependence of resistance, but this appears not to apply to the high temperature superconductors. The new technology is very well-suited to address all of these mysteries.

Open Technology Programme

The NWO Open Technology Programme provides funding for application-oriented technical-scientific research that is unrestricted and not hindered by disciplinary boundaries. The programme offers companies and other organisations an accessible way to participate in scientific research that is intended to lead to societal and/or scientific impact.