Ahmet Suna: PhD at Queen’s University Belfast, UK


Moveable Domain Wall Electronics in Single Crystal Ferroelectric Sheets


Professor Marty Gregg

Non-academic Supervisor:

Dr. Bernd Gotsmann (IBM Research Zurich, Switzerland)


Ahmet Suna is a Marie Curie Early Stage Researcher in Queen’s University Belfast, School of Mathematics and Physics. He received his Bachelor’s degree in Electronics and Communication Engineering, and his Master’s degree in Electronics Engineering from Istanbul Technical University in 2017 and in 2020 respectively. He has previously worked on analog & mixed-signal IC design, and his current research interest is in the development of ferroelectric domain wall based memristors, and their neuromorphic hardware integration.

Domain Walls in Memristive and Active Junction Devices

This project will seek to build on two recent discoveries: firstly, that conducting domain wall arrays in single crystal ion-sliced LiNbO3can act as excellent memristors, with accessible state densities comparable to those seen in ferroelectric tunnel junctions and unexplained synaptic “plasticity”; secondly, that both p-n and tunnel barrier junctions can exist inside domain walls themselves (in several improper ferroelectric systems), creating “in-domain wall” devices. Fully mapping and understanding the nature of both of these aspects of domain wall functionality is the main thrusts of the research. The main part of the research is performed at Queen’s University in Belfast. Additionally, Ahmet is spending the secondments at Ecole Polytechnique Federal de Lausanne, Switzerland for detailed domain wall characterization under SPM (1 Month) and at IBM Research – Zurich, Switzerland for the development of nanocircuitry (1 Month).

Queen’s University Belfast (QUB) was chartered in 1845 and opened in 1849 as “Queen’s College Belfast”. It is a vibrant university, which is strong in both teaching and research and sits comfortably within the top 200 in the world (QS World University Rankings). The main campus is situated beautifully, near to the city’s Botanical Gardens, Ulster Museum, Queen’s Film and Lyric Theatres. The university has a rich academic heritage in physics, with Paul Ewald (the Ewald Sphere) as an ex-member of staff and both Joseph Larmor (Larmor precession) and John Bell (Bell’s inequalities) as former students.

The environment for advanced functional materials research in QUB is enviable: researchers have ready access to excellent equipment and processing facilities, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), focused ion beam (FIB), atomic force microscopy (AFM), a superconducting quantum interference device (SQUID), interferometry, surface profilometry, pulsed laser deposition (PLD), magneto-optic Kerr effect microscopy (MOKE), sputtering, photolithography and Argon ion milling to name a few!