Multi-scale Investigation of the Nitride perovskite LaWN3: towards a functional integration in thin films
Lead Research Organisation:
University of Birmingham
Department Name: School of Chemistry
Abstract
MINd-LWN is a research project that will pave the way to controlling polar nitride perovskites by providing design strategies for their
integration into semiconductor devices without the loss of their intrinsic functionalities. Lanthanum tungsten nitride (LWN) is a polar
material in the emerging class of nitride perovskites. This new class of materials is of great interest for developing oxygen-free
functional materials, integrable in microelectronic devices and able to operate at a lower voltage. However, little is known about their
stability in thin films. LWN is theoretically predicted to be ferroelectric and thus able to display stable and ordered electric dipoles,
controllable through an electric field; therefore promising for memory applications in electronics. This material has recently been
synthesised in thin films but did not hold its promises: no ferroelectricity was experimentally verified, and measurements of its
stoichiometry revealed the presence of a significant concentration of nitrogen vacancies, likely interfering with its functionalities.
While control parameters such as temperature, defects, strain, and electrostatics have a crucial effect on electric dipoles, their role in
the context of nitride perovskites is unrevealed. Therefore, I propose a thorough theoretical study of the atomistic and electronic
structures and the polarisation properties of LWN thin films using advanced density functional theory and machine learning
techniques. Specifically, I will study the interplay between thickness, defect concentration, and temperature to understand and
control their influence on the ferroelectric stability. This project will set the scene for possible breakthroughs in the semiconductor
industry by allowing to merge decades of discoveries in perovskite materials with the intensive industrial development of
semiconductors. MINd-LWN will allow future the design of more efficient devices, which will have direct technological and economic
consequences.
integration into semiconductor devices without the loss of their intrinsic functionalities. Lanthanum tungsten nitride (LWN) is a polar
material in the emerging class of nitride perovskites. This new class of materials is of great interest for developing oxygen-free
functional materials, integrable in microelectronic devices and able to operate at a lower voltage. However, little is known about their
stability in thin films. LWN is theoretically predicted to be ferroelectric and thus able to display stable and ordered electric dipoles,
controllable through an electric field; therefore promising for memory applications in electronics. This material has recently been
synthesised in thin films but did not hold its promises: no ferroelectricity was experimentally verified, and measurements of its
stoichiometry revealed the presence of a significant concentration of nitrogen vacancies, likely interfering with its functionalities.
While control parameters such as temperature, defects, strain, and electrostatics have a crucial effect on electric dipoles, their role in
the context of nitride perovskites is unrevealed. Therefore, I propose a thorough theoretical study of the atomistic and electronic
structures and the polarisation properties of LWN thin films using advanced density functional theory and machine learning
techniques. Specifically, I will study the interplay between thickness, defect concentration, and temperature to understand and
control their influence on the ferroelectric stability. This project will set the scene for possible breakthroughs in the semiconductor
industry by allowing to merge decades of discoveries in perovskite materials with the intensive industrial development of
semiconductors. MINd-LWN will allow future the design of more efficient devices, which will have direct technological and economic
consequences.
