Local Piezoelectric Properties of Doped Biomolecular Crystals

authors	Kholkin, A; Alikin, D; Shur, V; Dishon, S; Ehre, D; Lubomirsky, I
nationality	International
journal	MATERIALS
author keywords	alpha-glycine; piezoelectricity; doping; piezoresponse force microscopy
keywords	GLYCINE
abstract	Piezoelectricity is the ability of certain crystals to generate mechanical strain proportional to an external electric field. Though many biomolecular crystals contain polar molecules, they are frequently centrosymmetric, signifying that the dipole moments of constituent molecules cancel each other. However, piezoelectricity can be induced by stereospecific doping leading to symmetry reduction. Here, we applied piezoresponse force microscopy (PFM), highly sensitive to local piezoelectricity, to characterize (01 over bar 0) faces of a popular biomolecular material, alpha-glycine, doped with other amino acids such as L-alanine and L-threonine as well as co-doped with both. We show that, while apparent vertical piezoresponse is prone to parasitic electrostatic effects, shear piezoelectric activity is strongly affected by doping. Undoped alpha-glycine shows no shear piezoelectric response at all. The shear response of the L-alanine doped crystals is much larger than those of the L-threonine doped crystals and co-doped crystals. These observations are rationalized in terms of host-guest molecule interactions.
publisher	MDPI
isbn	1996-1944
year published	2021
volume	14
issue	17
digital object identifier (doi)	10.3390/ma14174922
web of science category	7
subject category	Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter
unique article identifier	WOS:000694407800001