# David S Wisbey, Ph.D.

Assistant Professor
Physics

## Education

Postdoctoral Fellowship
NIST, Boulder, CO, 2008-2011

Degrees

• Ph.D., Condensed Matter Physics, Univ. of Nebraska-Lincoln, 2008
• M.S., Physics, Univ. of Nebraska-Lincoln 2005
• B.A., Physics, Union College, Lincoln, NE 2002

## Research Interests

Wisbey's research interests include materials for quantum computing, microwave resonators and amplifiers, and neutron detectors. Currently, he uses coplanar waveguides as a tool to probe different materials including defects in Si(100), boron nitride, and graphene. Noise in electronics is a fundamental issue that occurs in many different areas including 2D materials and superconducting circuits. Decoherence is generated by materials which quantum bits are made of, this is a major obstacle preventing a working quantum computer. His background in surface science is an invaluable tool he uses to address important questions about materials used in quantum computing. Wisbey works with many undergraduate students, which is helping to train the quantum scientists and quantum engineers of tomorrow.

## Labs and Facilities

The 3-Port Simulation Method File for Sonnet:

The following curve equation file can be inserted into Sonnet to calculate the local Q as:

FTYP EQUA 4! Sonnet Equations File

EQN “QZin3”
EQS USER FILE
EQD Calculate Q factor from input impedance of port3. EQH
Zin3=Z03*(1+s33)/(1-s33)
Q=f0/2*slope of imag(Zin3)/real(Zin3)
END EQH
AXISLABEL “Q”
ARGS 1
ARG 1!begin arg 1 definition
NAME s33
RES S 33
END ARG ! end of arg 1 definition
BODY
0.5*FREQ[f]*(imag(50*(1+s33[f])/(1-s33[f])) - imag(50*(1+s33[f-1])/(1-s33[f-1]))/(FREQ[f]-FREQ[f-1]) /real(50*(1+s33[f])/(1-s33[f]))
END BODY
END EQN

You will need to make sure it is the right format. Please email me and I would be happy to email a copy of my equation file.

## Publications and Media Placements

See Wisbey's LabVIEW Demo 2 Voltage Input and Output

Presentations

Incorporating Carbon Nanotubes into Superconducting Quantum Bits, D.T. Cherry, N. Thobabin, K. Zheng, R.L. Cooper, K. Murch, I. Kuljanishvili, D.S. Wisbey, APS March, Minneapolis, Minnesota 2024

The Effects of Gamma Radiation on Superconducting Microwave Resonators. D. Wisbey, N. Thobaben, D. Cherry, D. Kowsari, K. Zheng, K. Murch, R.L. Cooper, K. Goodman, Invited Talk, Distinguished Lecture Series, Naval Surface Warfare Center, Crane IN, August 2023.

Radiation effects on coplanar waveguide microwave resonators
Nathan J Thobaben, Daria Kowsari, Kaiwen Zheng, Grant Osmon, Abigail Sohm,  Denae Cherry, Kevin Goodman, Robert Cooper, Kater Murch, David S Wisbey, March Meeting, APS, Las Vegas Nevada, 2023.

Reducing Two-Level-System Microwave Loss in Niobium Resonators with Nitrogen Plasma Passivation. Kaiwen Zheng, Daria Kowsari, Nathan J. Thobaben, Xinyi Du, Sheng Ran, Erik A. Henriksen, David S. Wisbey, Kater W. Murch.  Presented at the March Meeting of the American Physical Society, Chicago, Illinois, 2022.

Fabrication and Surface Treatment of Electron-Beam Evaporated Niobium for Low-Loss Coplanar Waveguide Resonators, Daria Kowsari, Kaiwen Zheng, Jonathan T. Monroe, Nathan J. Thobaben, Xinyi Du, Patrick M. Harrington, Erik A. Henriksen, David S. Wisbey, Kater W. Murch. APS, March Meeting, Chicago, Illinois, 2022.

Niobium Coplanar Waveguide Microwave Resonators with Nitrogen Plasma Passivated Surface, Kaiwen Zheng, Daria Kowsari, David Wisbey, Kater Murch, MRS Fall Meeting, Boston, Massachusetts, 2021.

Ultra-High Vacuum Electron-Beam Evaporated Niobium for Low-Loss Superconducting Coplanar Waveguide Resonators, Daria Kowsari,Kaiwen Zheng, Jonathan Monroe,Nathan Thobaben, Xinyi Du,Patrick Harrington,Erik Henriksen, David Wisbey, Kater Murch, MRS Fall Meeting, Boston, Massachusetts, 2021.

Improving Materials for Quantum Computing, David Wisbey, Jacob Brewster, Jiansong Gao, Saint Louis University Department of Physics, 2018.

Using Superconducting Microwave Resonators to Measure the Dielectric Constant and Quality Factor of Ortho-Carborane-Capped Aluminum Nanoparticle Thin Films, Jacob Brewster, Xander Benziger, Paul Jelliss, David Wisbey, APS March Meeting, New Orleans, 2017.

Publications

Zheng, D. Kowsari, N. J. Thobaben, X. Du, X. Song, S. Ran, E. A. Henriksen, D. S. Wisbey, K. W. Murch, “Nitrogen Plasma Passivated Niobium Resonators for Superconducting Quantum Circuits”, Appl. Phys. Lett. 120, 102601 (2022).

Kowsari, K. Zheng, J. T. Monroe1, N. J. Thobaben, X. Du, P. M. Harrington, E. A. Henriksen, D. S. Wisbey, K. W. Murch, “Fabrication and surface treatment of electron-beam evaporated niobium for low-loss coplanar waveguide resonators”, Appl. Phys. Lett. 119, 132601 (2021).

T. Monroe, D. Kowsari, K. Zheng, C. Gaikwad, J. Brewster, D. S. Wisbey, K. W. Murch, “Optical direct write of Dolan–Niemeyer-bridge junctions for transmon qubits”, Appl. Phys. Lett. 119, 062601 (2021).

Wisbey, D.S., Vissers, M.R., Gao, J. Kline, J.S., Sandberg, M.O., Weides, M.P., Paquette, M.M., Karki, S., Brewster, J., Alameri, D., Kuljanishvili, I., Caruso, A.N., Pappas, D.P., J Low Temp Phys. 195, 474 (2019).

D. S. Wisbey, A. Martin, A. Reinisch, "New Method for Determining the Quality Factor and Resonance Frequency of Superconducting Micro-Resonators from Sonnet Simulations"
J. Low Temp. Phys. 176, 538-544, (2014).

M. R. Vissers, J. Gao, J. S. Kline, M. O. Sandberg, M. P. Weides, D. S. Wisbey, D. P. Pappas, "Characterization and in-situ monitoring of sub-stoichiometric adjustable superconducting critical temperature titanium nitride growth", Thin Solid Films 548, 485 (2013).

M. R. Vissers, J. Gao, M. O. Sandberg, S. M. Duff, D. S. Wisbey, K. D. Irwin, D. P. Pappas, "Proximity-coupled Ti/TiN multilayers for use in kinetic inductance detectors" Appl. Phys. Lett. 102, 23, 232603 (2013).

J. Gao, M. R. Vissers, M. O. Sandberg, F. C. S. da Silva, S. W. Nam, D. P. Pappas, D. S. Wisbey, E. C. Langman, S. R. Meeker, B. A. Mazin, H. G. Leduc, J. Zmuidzinas, K. D. Irwin, "A titanium-nitride near-infrared kinetic inductance photon-counting detector and it anomalous electrodynamics", Appl. Phys. Lett. 101, 142602, (2012).

M. Sandberg, M. R. Vissers, J. S. Kline, M. Weides, J. S. Gao, D. S. Wisbey, D. P. Pappas, "Etch induced microwave lasses in titanium nitride superconducting resonators", Appl. Phys. Lett. 100, 26, 262605 (2012).

M. R. Vissers, J. S. Kline, J. S. Gao, D. S. Wisbey, D. P. Pappas, "Reduced microwave loss in trenched superconducting coplanar waveguides", Appl. Phys. Lett. 100, 082602 (2012).

J. S. Kline, M. R. Vissers, F. C. S. da Silva, D. S. Wisbey, M. Weides, t. J. Weir, B. Turek, D. A. Braje, W. D. Oliver, Y. Shalibo, N. Katz, B.R. Johnson, T. A. Ohki, D. P. Pappas, "Sub-micrometer epitaxial Josephson junctions for quantum circuits.", Superconduc. Sci. Tech. 25, 025005 (2012).

M. P. Weides, J. S. Kline, 1 M. R. Vissers, M. O. Sandberg, D. S. Wisbey, B. R. Johnson, T. A. Ohki, D. P . Pappas, "Coherence in transmon qubit with epitaxial tunnel junctions", Appl. Phys. Lett. 99, 262502 (2011).
D. P. Pappas, M. R. Vissers, D. S. Wisbey, J. S. Kline, J. S. Gao, "Two Level System Loss in Superconducting Microwave Resonators", IEEE Trans. Appl. Supercond. 21, 871 (2011).

M. R. Vissers, J. Gao, D. S. Wisbey, D. A. Hite, C. C. Tsuei, A. D. Corcoles, M. Steffen, D. P. Pappas, "Low Loss Superconducting Titanium Nitride Coplanar Waveguide Resonators", Appl. Phys. Lett. 97, 232509 (2010).

D. S. Wisbey, J. Gao, M. R. Vissers, F. C. S. Da Silva, J. S. Kline, L. Vale, D. P. Pappas, "Effect of metal/substrate interfaces on RF loss in superconducting coplanar waveguides", J. Appl. Phys. 108, 093918 (2010)