CBC’s New Instrument for Revolutionizing Computing and Energy Research

By Oliver Monti

While we have all become used to the ever-increasing speed of computers empowering our daily lives, fundamental scientific principles tell us that the pace of progress in the last five decades cannot be sustained.

The need for increased computer speed is running into the hard wall of ultimate miniaturization of computer chips that by now operate at nearly an atomic scale. Massive scientific breakthroughs are necessary to enable radically different kinds of computers to keep increasing their speeds and to meet the exponentially increasing demand for data storage and processing. Just as pressing is the need for dramatically increased energy efficiency in computing, and for largescale production and storage of renewable energy. This requires pivoting from traditional semiconductors such as Si to make computer chips or solar cells to new architectures based on novel quantum materials.

Quantum materials are crystalline materials whose extraordinary properties arise from strong electron-electron interactions. Some of these materials may be just a few atoms high, creating extended truly two-dimensional materials. Others use heavy elements which allows materials chemists to take advantage of the special properties of electron spin to encode information or transfer energy. The unique properties of quantum materials may enable transport of electrons without friction, encode information securely without risk of being hacked, or dramatically increase energy efficiency in information processing applications. Some quantum materials are also candidates for novel concepts in energy harvesting, e.g., converting heat to electricity with exceptional efficiency.

The study of such materials and their integration into devices requires a closeup look into their electronic structure. To this end, under the leadership of Prof. Oliver Monti, CBC is bringing online the

first high-resolution electronic structure

microscope in the United States. Since electron-electron interactions are at the heart of the special properties of quantum materials, new methods are needed to reveal their electronic structure. The electronic structure microscope (nanoESCA) relies on photoelectron spectroscopy, where photoemitted electrons carry a fingerprint of the chemical and electronic structure of the material. The microscope achieves this while for the first time also imaging the emitted electrons anywhere on the sample, thereby providing a high-resolution chemical, electronic and spatial map of the quantum material under investigation. ity (EPSILON-UArizona) located in the Department of Chemistry and Biochemistry, this microscope reveals chemical composition and state, and measures the electronic structure of new materials at the sub-micron level. Such detailed information has thus far been out of reach for the critical task of probing, understanding and engineering novel miniaturized information processing and green energy conversion and storage devices.

The chemical and electronic information together with high-spatial resolution enables ground-breaking research from quantum materials to renewable energy technologies, and from battery research to geochemistry. EPSILON-UArizona will operate as a regional, national, and international resource attracting researchers from around the globe to this facility to carry out investigations on nanoscale materials. It will be managed by Paul Lee, a long-term staff scientist in CBC who is also in charge of the Laboratory for Electron Spectroscopy and Surface Analysis.

Sara Zachritz, Anubhab Chakraborty, and Joohyung Park, students in Oliver Monti’s lab, working on the microscope. The microscope is about 9 ft tall, and 8 ft by 6 ft wide. Samples can be cooled to 30 K or heated to 1000 K.