Developing the field of quantum information science (QIS) hinges upon designing viable qubits, the smallest unit in quantum computing. One approach to creating qubits is introducing paramagnetic defects into semiconductors or insulators. This class of qubits has seen success in the form of nitrogen-vacancy centers in diamond, divacancy defects in SiC, and P doped into Si. These materials feature paramagnetic defects in a low-nuclear-spin environment to reduce the impact of nuclear spin on electronic spin coherence. In this work, we report single-crystal growth of Ba2CaWO6-δ and the coherence properties of introduced W5+ spin centers generated by oxygen vacancies. Ba2CaWO6-δ (δ=0) is a B-site ordered double perovskite with a temperature-dependent octahedral tilting wherein oxygen vacancies generate W5+ (d1), S=1/2, I=0, centers. We characterized these defects by measuring the spin-lattice (T1) and spin-spin relaxation (T2) times from T=5-150K. At T=5K, T1=310ms and T2=4μs, establishing the viability of these qubit candidates. With increasing temperature, T2 remains constant up to T=60K and then decreases to T2∼1μs at T=90K, and remains roughly constant until T=150K, demonstrating the remarkable stability of T2 with increasing temperature. Together, these results demonstrate that systematic defect generation in double-perovskite structures can generate viable paramagnetic point centers for quantum applications and expand the field of potential materials for QIS.
ASJC Scopus subject areas
- Materials Science(all)
- Physics and Astronomy (miscellaneous)