Prof. Dr. Martin Salinga

We characterize the dynamics of our nanostructured samples over orders of magnitude in time both with electrical and ultrafast optical measurements. These measurements are complemented with ab-initio simulations based on density functional theory, which offer access to quantities that are not or not easily accessible with experiments. In close connection to our experimental work, we aim at a deeper understanding of the mechanism of electronic transport in amorphous materials at the nano-scale, which is essential to understand the behavior of nanoscopic memory elements.

Devices based on phase change materials can be used in novel processors, which are inspired by computing paradigms of our brain. Today, almost all of our computers are based on the von Neumann architecture, where processing and memory are separated. Hence, data must be shipped back and forth between the processing unit and memory, which is costly in terms of time and energy. In-memory computing, in contrast, breaks with the von Neuman paradigm by collocating processing and memory. This is especially useful for calculating matrix-vector multiplications, which make the majority of calculations performed in artificial neural networks.

Therefore, new memory technologies are object of intense research to develop novel electronic and photonic in-memory processors. Their distinct property contrast between the crystalline and amorphous states along with their ability to crystallize within nanoseconds makes phase change materials well suitable for these applications. The contrast in electrical resistance is exploited in electronic memory cells and the optical contrast in attenuators and interferometers for integrated photonics. Optimal performance in a specific application, however, can only be reached when tailored materials with optimized properties are used.