Combining lattice and electronic dynamics with functional material properties is a holy grail for condensed matter science. For example, combing semiconducting and magnetic states in a material would enable the unlocking of spin-based electronics such as non-volatile transistors, which are key for low-energy computing [1]. In this talk I will detail our efforts towards lattice-based control of material properties in two important areas.
I will start by discussing our efforts to couple semiconducting and magnetic properties in 2D materials. So-far such magnetic semiconductors have only been observed in doped oxide systems and/or at low temperatures. I will discuss our recent discovery of magnetic and semiconducting properties in nanometre strips of monolayer black phosphorus - phosphorene nanoribbons (PNRs) [2]. I will show that PNRs exhibit macroscopic magnetic properties, arising from their edge, with internal fields of up to 800 mT (in thin films). I will then detail how the magnetism in PNRs is coupled to low energy symmetry forbidden edge phonon modes, providing a novel route to lattice control of their magnetism.
In the second part of my talk, I will discuss our efforts to understand ultrafast lattice dynamics in Li-ion battery materials. I will show how using far-IR, THz and X-ray free-electron lasers we can potentially probe the transition state of ion hops and the associated with nascent charge motion in operating batteries. Our results here provide routes towards lattice engineering of battery materials and generally probing important ultrafast processes e.g., polaron formation, in these systems [3].

References:
[1] Ando et al Science (2006) 312 5782
[2] Ashoka et al. arXiv:2211.11374 [cond-mat.mes-hall]
[3] Sood et al. Nat. Rev. Mat. (2021) 6 847-867