Challenge:

Phase change materials are characterized by a rapid transformation between amorphous and crystalline phases, meaning between highly disordered to highly ordered inter-atomic ordering. The phase transformation happens upon external triggering of a light or heat pulses, leading to drastic change in properties, such as, the optical opacity, opto-electronic, or change transport.  Since the properties often defined by a volume fraction for the particular order states of the meta-stable material, one can create a continuously switchable functionality. Continuously switchblade conductivity, for example, especially when reduced to the nano-scale, is exactly the basis of a non-volatile phase change memory device that can be used for neuromorphic computation (recommended read).

The challenge is to understand the details of the phase evolution during phase transformation, and how the distribution of phases impact the properties and stability of the assembly. In particular challenging is the ability to understand and stitch togeter a coherent picture between a highly ordered and highly disordered states,  to understand what is happening in that transition, and to control it.

Mission :

Our mission is to understand the early stages of evolution within the glassy phase, meaning during nucleation and early growth. We target materials for advance applications, such as neuromorphic computation, energy recycling and storage. We are interested in providing knowledge that will be used to control the phase transformation and the final stability of a resulting meta-stable phases - mostly at the nano-metric length-scales. Our focus will be on chalcogenide-glass (e.g., Ge 2 Sb 2 Te 5 ), and related compounds, known also as 'fragile' glasses. For example, we will be looking after external and internal triggers that activate, or hinder, crystallization, and relate the different states     to charge and thermal transport properties.