In Memoriam: Charles S. Fadley, Longstanding Collaboration Partner, Power User, Advisor

Charles ‘Chuck’ S. Fadley, a pioneer in photoemission spectroscopy and internationally renowned Distinguished Professor Emeritus of Physics at the University of California, Davis, and Senior Faculty Scientist at the Lawrence Berkeley National Laboratory, USA, passed away on the 1st of August 2019. He remained an active and avid researcher until a few weeks before his death at age 77.

Anyone who spent any length of time working with x-ray photoemission spectroscopy would eventually come to the point where they would no longer be surprised to walk into any meeting, lab, or conference, anywhere, and find Chuck already there, ahead of them. The same thing could happen if you thought you had a new idea. So, there is no surprise in saying that Chuck has left his mark in the photoemission-related areas of BESSY II.

Chuck was one of the most important promoters of the Energy Materials In-Situ Laboratory Berlin (EMIL). Between 2013 and 2017, Chuck was the head of the EMIL International Advisory Committee that counselled the HZB Board of Directors and the Scientific Advisory Committee on the EMIL facility and its operation, scientific topics, optimization of the instruments, and collaborations with institutes and industry. He offered his outstanding expertise on X-ray photoelectron spectroscopy in elaborate recommendations for the operation and future development of EMIL, helping make it a truly unique and innovative facility.

Chuck was also an active researcher at BESSY II where he worked, among other things, on novel magnetoelectric interfaces for low-power spintronics. He also explored new approaches to studying subsurface structures; a very challenging endeavor considering that the probing depth of X-ray photoelectron spectroscopy is limited to the first few layers beneath a solid surface. Together with colleagues at BESSY II, Chuck developed the so-called “swedge method”: after growing a multilayered sample on top of a nanometer-scale, multilayered mirror, the exciting radiation field can be 'tailored' into an oscillatory standing wave of the same length scale. For the first time, they showed that this standing wave can be deliberately moved up and down within the sample layers, providing excellent depth (z) resolution in photoemission studies.

Chuck received several awards  for his outstanding scientific achievements.

His ability to develop new ideas and to inspire colleagues made Prof. Chuck an exceptional partner to work with. Our thoughts are with his family. We will miss him as a brilliant colleague and a dear, colorful friend, and will cherish his memory.