Anomalous Spin-Electric Effects in the [VO(TPP)] Nanomagnet

[VO(TPP)], a metal-organic molecular nanomagnet, has shown many interesting physical properties including coherence times of T₂ ~ 0.5 μs.^1,2 At the center of the molecule a double polar bond between the vanadium and oxygen gives rise to strong hyperfine coupling between the nuclear I = 7/2 and electronic S = 1/2 states, producing hybridized spin states that can be clearly identified using electron-spin resonance (ESR). At S-band frequencies, we observe eight spin-state transitions consistent with the known hyperfine coupling in this system. The spectrum remains largely unaffected by an applied static electric field below a critical field strength. When an electric field above ~3×10^5 V/m is applied, however, we observe a distinct change to the spectrum: the eight transitions are highly diminished and the spectrum becomes dominated by a single strong spin transition. We present first steps toward characterization and explanation of this behavior.

¹T. Yamabayashi, et. al., J. Am. Chem. Soc. 140, 12090-12101 (2018).

²C. Bonizzoni, et. al., npj Quantum Inf 6, 68 (2020).