Physics Colloquium

Harnessing spin crossover phenomena: Thermodynamically stable voltage control of spin states at the ferroelectric interface

Aaron Mosey

Abstract: It is well known that thermal constraints and the quantum limit will soon put a boundary on the scale of micro and nanostructure based electronic devices. Thermodynamic stability at room temperature, fast (Ghz) switching, and low energy cost narrow the list of material candidates for next generation electronics. Molecular based devices are one promising candidate to facilitate the post-Moore's era of design. Molecular electronic frontier orbitals of some d-block transition metal ions in octahedral fields deform in response to the local energetic environment, giving rise to the e_g and t_2g suborbitals. The energetic scale between these two orbitals yields the S=0 low spin (LS) diamagnetic state and the S=2 high spin (HS) paramagnetic state. The switching between HS and LS states is traditionally facilitated by temperature, photon or pressure stimuli, and this switching is also accompanied with change of conductivity. Here we report a stable, room temperature locking and unlocking of the spin states, controlled by electrical voltage, when spin crossover (SCO) complex [Fe(II)(H₂B(pyz)₂(bipy))₂] is in proximity to a ferroelectric polyvinylidene fluoride hexafluropropylene (PVDF-HFP) polymer. This study opens a door to the creation of a thermodynamically stable room temperature multiferroic gated voltage device. 

Flyer

Refreshments will be served in LD 154B from 3:00-3:30pm.