Spectroscopy and control of spin-strain interactions for Group-IV color centers in diamond membranes
Abstract
Oscillating and static strain in solid-state materials are widely utilized in next generation technologies in quantum phononics and quantum networking. In this proposal, we acquire instrumentation to explore the interaction of strain and quantum properties of diamond qubits. In particular, we focus on so-called Group-IV color center qubits in diamond. When quantized phonons are tightly co-localized with Group-IVs in acoustic cavities, the electron spins of the center can potentially enter the strong coupling regime with the phonons. Strong spin-phonon coupling has broad technological implications, including compact control and efficient routing of quantum information at the chip scale. Furthermore, phonons can serve as a coupling link between superconducting qubits and solid-state spins. This can allow long-lived spin qubits to serve as quantum memories in superconducting quantum circuits, and also provides a direct transduction pathway between GHz and THz light. In the DC regime, strain can beneficially modify the electronic structure of group IV color centers, leading to exponentially reduced phonon-induced spin-dephasing of the electron spin at higher operating temperatures. This can allow coherent, controllable qubits for quantum networking that operate above 4K, significantly easing the cost and complexity of quantum nodes that utilize Group-IV centers.We are able to create thin membranes of diamond that host coherent Group-IV color centers, and directly bond them to other materials. This opens up a wealth of possibilities to control the strain environment of the Group-IVs in both the static and oscillating regime. To explore quantum spin-phonon interactions, we can directly bond thin films of diamond - which has no piezoelectric response - with lithium niobate (LN) - a piezoelectric material that is broadly utilized in acoustic physics. This heterogeneous platform allows us to create and control surface acoustic waves (SAWs) on LN that can directly interact with color centers in diamond. By co-designing optimal photonic and acoustic structures, we can simultaneously localize color centers at the maximum field intensity of cavity-confined SAWs while enabling efficient optical spin readout of color centers. Additionally, we have demonstrated that by simply bonding diamond membranes to fused silica substrates, we can controllably generate strain profiles in the membranes. This strain, on the order of 0.1-0.5percent, dramatically modifies the electronic structure of group-IVs and in turn the spin-coherence and microwave control of the system.Through the DURIP proposal, we will acquire a low-temperature, vector-magnet measurement platform to perform precision studies of spin-strain interaction and to control spin-phonon interactions. While our diamond membrane platform creates a wealth of opportunities to explore and control strain interactions, there are significant, unresolved questions regarding spin-strain interactions that must be addressed through tunable magnetic field measurements at low temperature. In the AC regime, the tunable magnetic field will allow us to control the coupling between spins and acoustic-cavity phonons and directly measure the spin-phonon interaction strength. In the DC strain regime, a low-temperature vector-magnet system is necessary to experimentally probe the electronic structure of strained Group-IVs, in which the strain directly competes with spin-orbit coupling. These studies will broadly benefit research in quantum phononics and strain engineering, both of which are Department of Defense-supported research areas.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 06, 2024
- Source ID
- FA95502310459
Entities
People
- Alexander A. High
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Chicago