TY - JOUR
T1 - Excited Spin-State Trapping in Spin Crossover Complexes on Ferroelectric Substrates
AU - Wäckerlin, Christian
AU - Donati, Fabio
AU - Singha, Aparajita
AU - Baltic, Romana
AU - Decurtins, Silvio
AU - Liu, Shi Xia
AU - Rusponi, Stefano
AU - Dreiser, Jan
N1 - Funding Information:
J.D. and C.W. gratefully acknowledge funding from the Swiss National Science Foundation (grant no. PZ00P2_142474). C.W. acknowledges financial support from the University of Zurich priority program LightChEC. F.D. acknowledges support from IBSR027-D1. The authors thank Stephan Keller for assistance with the synthesis. Also, they thank Cinthia Piamonteze and Jakoba Heidler for assistance with the ferroelectric poling setup.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/4/19
Y1 - 2018/4/19
N2 - We have studied thin films of Fe(II) spin crossover complexes deposited on differently poled ferroelectric PMN-PT ([Pb(Mg1/3Nb2/3)O3]1-x[PbTiO3]x, x = 0.32) substrates by X-ray absorption spectroscopy. The X-ray spectra reveal the temperature-driven conversion between high-spin and low-spin states without any observable effect of the ferroelectric polarization on the spin state of the molecules down to 100 K. In the soft X-ray-induced excited spin-state trapping (SOXIESST) regime at 3 K, large differences occur between the two ferroelectric polarizations. The efficiency of X-rays in exciting the molecules to the high-spin state is more than an order of magnitude larger when the ferroelectric dipoles of the substrate are pointing toward the surface compared to the opposite polarization. We explain our findings by a modulation of the polarization-dependent efficiency of the scattering of X-ray-generated secondary electrons at the molecules. Our results provide a deep insight into the SOXIESST mechanism and suggest that such molecules could be used as detectors for electrons traveling in the substrate at energies lower than the substrate electron affinity.
AB - We have studied thin films of Fe(II) spin crossover complexes deposited on differently poled ferroelectric PMN-PT ([Pb(Mg1/3Nb2/3)O3]1-x[PbTiO3]x, x = 0.32) substrates by X-ray absorption spectroscopy. The X-ray spectra reveal the temperature-driven conversion between high-spin and low-spin states without any observable effect of the ferroelectric polarization on the spin state of the molecules down to 100 K. In the soft X-ray-induced excited spin-state trapping (SOXIESST) regime at 3 K, large differences occur between the two ferroelectric polarizations. The efficiency of X-rays in exciting the molecules to the high-spin state is more than an order of magnitude larger when the ferroelectric dipoles of the substrate are pointing toward the surface compared to the opposite polarization. We explain our findings by a modulation of the polarization-dependent efficiency of the scattering of X-ray-generated secondary electrons at the molecules. Our results provide a deep insight into the SOXIESST mechanism and suggest that such molecules could be used as detectors for electrons traveling in the substrate at energies lower than the substrate electron affinity.
UR - http://www.scopus.com/inward/record.url?scp=85045737288&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.7b10941
DO - 10.1021/acs.jpcc.7b10941
M3 - Article
AN - SCOPUS:85045737288
SN - 1932-7447
VL - 122
SP - 8202
EP - 8208
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 15
ER -