A molecular approach to quantum information science

Quantum information science promises to revolutionize the way we perform computation, enabling the use of fundamentally new algorithms for applications such as quantum simulation and quantum cryptography. However, in order to build a functional quantum computer, scientists will first have to find a way to build scalable architectures assembled from modular components. Paramagnetic coordination complexes are the ideal components for such an approach, given the inherent quantum nature of the unpaired electrons and the ability to tune their energy levels through chemical modifications. We explore the sensitivity of these quantum states by performing detailed magnetic and spectroscopic measurements on carefully curated families molecular complexes, ultimately leading to new design parameters.

Select Publications

A Porous Array of Clock Qubits
Zadrozny, J. M.; Gallagher, A. T.; Harris, T. D.; Freedman, D. E. J. Am. Chem. Soc. 2017, 139, 7089–7094.

Synthetic Approach to Determine the Effect of Nuclear Spin Distance on Electronic Spin Decoherence
Graham, M. J.; Yu, C.; Krzyaniak, M.; Wasielewski, M.; Freedman, D. E. J. Am. Chem. Soc. 2017, 139, 3196–3201.

Long Coherence Times in Nuclear Spin-Free Vanadyl Qubits
Yu, C.; Graham, M. J.; Zadrozny, J. M.; Niklas, J.; Krzyaniak, M.; Wasielewski, M. R.; Poluektov O. G.; Freedman, D. E. J. Am. Chem. Soc. 2016, 138, 14678–14685.

Influence of Electronic Spin and Spin-Orbit Coupling on Decoherence in Mononuclear Transition Metal Complexes
Graham, M. J.; Zadrozny, J. M.; Shiddiq, M.; Anderson, J. S.; Fataftah, M. S.; Hill, S.; Freedman, D. E. J. Am. Chem. Soc. 2014, 136, 7623–7626.

Extreme pressure as a synthetic vector

We are pursuing the synthesis of exotic new solid-state compounds through the use of extremely high static pressure as a synthetic vector. Certain pairs of elements do not form intermetallic compounds over any combination of temperature and composition, but this does not mean that such compounds are impossible, simply that a thermodynamic approach under ambient pressures is not appropriate. One way we are accessing our targeted metastable compounds is to perform solid-state reactions under pressures comparable to planetary cores, where these phases are the thermodynamic product. In some cases, these compounds can be recovered to ambient pressures and temperatures, where they are metastable—much like diamond is a recovered metastable phase of carbon formed at high pressure. We have used this approach to discover a number of new compounds and bonds in systems that do not react under ambient pressures.

Select Publications

High-Pressure Discovery of β-NiBi
Powderly, K. M.; Clarke, S. M.; Amsler, M.; Wolverton C.; Malliakas, C. D.; Meng, Y.; Jacobsen, S. D.; Freedman, D. E. Chem. Commun. 2017, 53, 11241–11244.

Creating Binary Cu–Bi Compounds via High-Pressure Synthesis: A Combined Experimental and Theoretical Study
Clarke, S. M.; Amsler, M.; Walsh, J. P. S.; Yu, T.; Wang, Y.; Meng, Y.; Jacobsen, S. D.; Wolverton, C.; Freedman, D. E. Chem. Mater. 2017, 29, 5276–5285.

Discovery of FeBi2
Walsh, J. P. S.; Clarke, S. M.; Meng, Y.; Jacobsen, S. D.; Freedman, D. E. ACS Cent. Sci. 2016, 2, 867–871.

Discovery of a Superconducting Cu–Bi Intermetallic Compound by High-pressure Synthesis
Clarke, S. M.; Walsh, J. P. S.; Amsler, M.; Malliakas, C. D.; Yu, T.; Goedecker, S.; Wang, Y.; Wolverton, C.; Freedman, D. E. Angew. Chem. Int. Ed. 2016, 55, 13446–13449.

Chemical approaches to emergent properties

Targeted synthetic approaches can lead to fundamentally new materials that display exotic spin physics. For example, the synthesis of systems with spin-bearing ions arranged on a perfect triangular lattice is one route toward a bulk state known as a spin liquid. Candidate systems sometimes appear in nature, or through serendipitous discovery, but guided by physicists we should be able to judiciously design and isolate systems with the required properties. We are targeting new materials in this way, using unconventional approaches toward synthesis, to create new materials that will help us to answer outstanding questions in magnetism, superconductivity, and condensed matter physics.