Topotronic multi-dimensional spin hall nano-oscillator networks
TOPSPIN will focus on spin Hall nano-oscillators (SHNOs), which are nano-sized, ultra-tunable, and CMOS compatible spin wave based microwave oscillators. TOPSPIN will push the boundaries of SHNO lithography, frequency, speed, and power consumption by combining topological insulators, having record high spin Hall efficiencies, with materials having ultra-high spin wave frequencies. TOPSPIN will reduce the required current densities 1-2 orders of magnitude compared to state-of-the-art, making SHNO operating currents approach 1 uA, and increase the SHNO operating frequencies an order of magnitude to as high as 300 GHz. 

TOPSPIN will use mutually synchronized SHNOs to achieve orders of magnitude higher signal coherence and achieve novel functionality such as pattern matching and neuromorphic computing. TOPSPIN will demonstrate mutual synchronization of up to 1,000 SHNOs in chains, and as many as 1,000,000 SHNOs in very large-scale two-dimensional arrays. Using dipolar coupling between SHNOs fabricated on top of each other, three-dimensional mutual synchronization will also be demonstrated. As the signal coherence increases linearly with the number of mutually synchronized SHNOs the oscillator quality factor will improve by many orders of magnitude. TOPSPIN will also develop such arrays using magnetic tunnel junction stacks thus combining ultra-high coherence with the highest possible microwave output power.

TOPSPIN will demonstrate ultrafast pattern matching and neuromorphic computing using its SHNO networks. It will functionalize SHNOs to exhibit ultra-fast individual voltage controlled tuning and non-volatile tuning of both the SHNO frequency and the inter-SHNO coupling. 

TOPSPIN will characterize its SHNOs using novel methods and techniques such as multichannel electrical measurements, time- and phase-resolved Brillouin Light Scattering microscopy, time-resolved Scanning Transmission X-ray Microscopy, and ultrafast pump-probe Transmission Electron Microscopy.