Dr. Theis joined the Department of Semiconductor Science and Technology at the IBM Watson Research Center to study electronic properties of two-dimensional systems. He also collaborated in research on surface enhanced Raman scattering, light emission from tunnel junctions, and conduction in silicon dioxide. The latter work helped to lay the basis for the present understanding of conduction in wide band-gap materials. In 1982 he became manager of a group studying growth and properties of III-V semiconductors. He published extensively on the DX-center, a donor-related defect which limits the digital performance of some III-V transistors. In 1989 he was named Senior Manager, Semiconductor Physics and Devices. In 1993 he was named Senior Manager, Silicon Science and Technology, where he was responsible for exploratory materials and process integration work bridging between Research and the IBM Microelectronics Division. While in this position, he was the principal author of IBM's successful contract proposal for the DARPA Low Power Electronics Program. This fifteen million dollar, three year, industry-university-SEMATECH joint program significantly advanced silicon-on-insulator materials, devices, and design techniques for low-power, high-performance microelectronics. Also while in this position, Dr. Theis organized the transfer of copper interconnection technology from IBM Research to the IBM Microelectronics Division. The replacement of aluminum chip wiring by copper was an industry first, the biggest change in chip wiring technology in thirty years, and involved close collaboration between research, product development, and manufacturing organizations. Dr. Theis assumed his current position, Director, Physical Sciences, in February 1998. In this position he is responsible for IBM's world-wide investments in research in the physical sciences. At present, approximately two thirds of this investment is in nanoscale science and technology.

Dr. Theis is a member of the IEEE, the Materials Research Society, a Fellow of the American Physical Society and currently serves on advisory boards for the American Institute of Physics Corporate Associates and the National Nanofabrication Users network, and is a Member of the Committee for the Review of the National Nanotechnology Initiative, sponsored by the National Research Council. He has authored or co-authored over 60 scientific and technical publications.