Peter H. Jacobse
pushing the boundaries of nanomaterials and technology
We made graphene nanoribbons with magnetic properties! Check it out!
I am Peter Jacobse, a researcher, engineer, micronaut and carbon architect based in the San Francisco Bay Area. My resume can be found here.
I am a micronaut: someone who loves to explore (E, x, y, z)-space (and its Fourier counterparts in reciprocal space) of surfaces and molecules using scanning probe microscopy and hyperspectral analysis techniques. I am an expert skilled in scanning probe microscopy (scanning tunneling (STM) and atomic force microscopy (AFM)) with more than a decade and several tens of papers under my belt, and have a particular knack for ultra-high resolution mapping of transport and electronic structure of materials, down to individual molecular orbitals.
I am a carbon architect: someone who loves to build interesting structures; but my building blocks are atoms and chemical bonds instead of bricks and steel. I use chemical reactions instead of concrete to assemble the structures that I am interested in. Then, I zoom in on the new quantum mechanical properties that they exhibit. The nanostructures that I make are of interest for use in faster, smaller, smarter and more energy-efficient nanoelectronics, including spintronics and quantum computing. Recent breakthroughs in the realms of machine learning (ML) and artificial intelligence (AI) are straining computational resources more than ever, and I am working hard on exploring the materials of the future to facilitate these developments. More recently, I have been exploring biomolecules on surfaces, like DNA.
I am a former postdoctoral researcher at the University of California, Berkeley in the group of Michael F. Crommie, where my research focused on designing, building and analyzing carbon-based nanostructures on surfaces. One of my favorite materials is graphene nanoribbons - narrow strips of the wonder material graphene - which are excellent conductors of electricity. I have been at the forefront of developing strategies to engineer electron spin and magnetism in nanoribbons and carbon-based lattices. Magnetism and spin are important ingredients for data storage, spintronics (a greener, more energy-efficient alternative to electronics) and quantum computing.
More recently, I have been part of a hard-tech Silicon Valley startup in stealth mode. As part of my daily work, I have been carrying out STM research at the Lawrence Berkeley National Lab, have been co-designing a new type of device for a yet undisclosed purpose, and have been performing tons of CAD design, vacuum chamber builds and electronics design to make this a reality.
I have been at the forefront of the development of techniques to improve the synthetic capabilities of carbon-based nanostructures. For example, I have pioneered matrix-assisted direct transfer, an important technique to bring polymers and macromolecules onto the surface and turn them into graphene nanoribbons, after they have been prepared by chemists. In addition, I have been at the forefront of turning carbon-based nanomaterials into actual devices that function as real transistors, and I have made steps in making new kinds of structures with different electronic properties.
But in addition, I have also fostered engineering skills. I work regularly with computer-aided design (CAD) and electronics CAD (ECAD) to engineer the parts, chambers, and circuit boards that I need to carry out my research. In the picture on the right, you can see me holding a circuit board I designed myself, standing in front of an electrospray ionization chamber I have designed and built myself as well, containing a plethora of custom-designed parts like sample holders and spray nozzles. For electrical engineering, I am knowledgeable on the entire signal processing chain from sensor to ADC/mux to spi/I2C communication to microprocessor/FPGA to demux/DAC to actuation.
My work combines insights from synthetic organic chemistry, theoretical and experimental physics, surface science, nanoscience, electrical and mechanical engineering. As such, I fulfill a very interesting, interdisciplinary role in academia/industry, where I am particularly comfortable collaborating with chemists, theoretical and experimental physicist, engineers, contractors and tech companies. I am passionate about my interdisciplinary research, my role as collaborator and interpreter between all these different people and perspectives, and my role as someone who is pushing the boundaries of science and technology.
The techniques that I work with are called scanning probe microscopy (SPM), which encompasses scanning tunneling microscopy (STM), atomic force microscopy (AFM) and their force/current spectroscopy counterparts. These are incredibly powerful methods that allow me to look at structures down to atoms. The machine that I work with is housed in an ultra-high vacuum (UHV) chamber, which we pump down to an incredible vacuum of only 0.0000000001% of atmospheric pressure: a more perfect vacuum than what you will find near the international space station. We typically conduct measurements at a chilly 4.5 degrees Celsius above absolute zero: a temperature needed to "freeze" our molecules and nanoribbons to the surfaces we are probing. We are actively trying to combine our scanning probe spectroscopy techniques with laser experiments, spin-polarized tips, magnetic fields and electron-spin resonance, in order to reveal all of the interesting quantum mechanical effects lurking in the structures that we are interested in. Our aim is to also use these parameters to manipulate our structures and potentially use them as qubits or spintronic devices.
Performing research with such instruments is not always straightforward, and when it breaks down, you need to fix it. That's right. I'm not just an architect (and scientist, paper writer, mentor, theoretician, graphics designer, etc) but I am also a surgeon! Because of numerous times of hardship in the lab, I have become an expert at fixing and engineering STMs and other ultra-high vacuum equipment! See these photos for a little impression of life in the lab.
Among my scientific achievements are the fabrication of nanoporous graphene (transistors) as well as new types of electronically functional graphene nanoribbon heterostructures and quantum dots. I have experimentally revealed the phenomenon of negative differential resistance in graphene nanoribbons. I have made and studied graphene nanoribbons with four-membered rings and five-membered rings, as well as magnetic nanoribbons. I am a leading expert on nitrogen doping in graphene nanoribbons. I have provided fundamental insights into the mechanisms of on-surface chemistry reactions through my work utilizing noncontact-AFM and x-ray photoelectron spectroscopy (XPS). I am an expert in graphene nanoribbon transport through my work on in-situ lifting/transport measurements and transport calculations. I have developed a software package for performing electronic structure calculations at the level of tight-binding/mean field Hubbard theory, called MathemaTB. I have developed new surface-synthesis techniques such as matrix-assisted direct (MAD) transfer, which vastly increased the scope of nanostructures accessible on surface. I have used MAD transfer in conjunction with protecting-group aided iterative synthesis (PAIS) to achieve, for the first time, the fabrication of fully monodisperse graphene nanoribbons with precisely predetermined length and monomer sequence.
