NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY – About the Group

The solid state NMR group at a glance

The solid state NMR (ssNMR) group of INN works primarily in the area of Condensed Matter Physics, focusing in the study of strong electron correlated systems, topological matter, as well as the study of the electronic properties of various nanocatalysts, such as transition-metal based phosphide nanoparticles, supported 2D dichalcogenides (e.g. MoS2), nanozeolites, etc. Other areas of interest are NMR studies of nanofluidic processes in restricted geometries (e.g. water and ionic liquid motion in carbonaceous and silica nanoporous structures), as well as gelation processes of industrial interest, such as cements, and self-healing coatings for the aerospace technology.

Photo of the Group: (from left to right): Back Seats: Mr Orfanidis Savvas, Mr Subrati Ahmed, Mr Subrati Mohammed, Ms Gkoura Lydia, Mr Anastasiou Athanasios Front Seats: Dr. Fardis Michalis, Dr. Papavassiliou George, Dr. Karagianni Marina, Dr. Panopoulos Nikolaos

In the last years the ssNMR group is strongly involved in the implementation of NMR crystallography methods in the study of metals and semi-metals with complex electronic properties (combining advanced ssNMR methods with Density Functional Theory (DFT) methods to acquire precise electronic and crystallographic information at the nanoscale). Work in this area is in collaboration with the Stockholm university (Sweden), the university of Lyon (France), the Korea Basic Science Institute (S. Korea), and the Khalifa university of Science and Technology at Abu Dhabi (UAE).

Weyl fermions detected with Electron-Energy-States-Resolved NMR crystallography: Experimental 2-D 125Te adiabatic Magic Angle Turning (aMAT) NMR spectrum (a) and DFT calculated (b), confirm the k-resolved projected DOS in the Weyl semimetal WTe2 (c-f). (preprint in arXiv:2110.01300 [cond-mat.mtrl-sci] (2021), https://arxiv.org/abs/2110.01300).

 

31P NMR nanocrystallography on Ni2P: Theoretical and DFT calculated  31P NMR spectrum of Ni2P. Input in DFT was the crystallographic data acquired by XRD. (Nature Communications | (2021) 12:4334 | https://doi.org/10.1038/s41467-021-24589-5).

125Te NMR study of the Topological Insulator Bi2Te3: 2D 125Te adiabatic Magic Angle Turning (aMAT) NMR and 125Te NMR effective spin-spin relaxation T’2 distribution with respect to the resonance frequency enable the detection of exotic topological Dirac electron states at the surface of Bi2Te3 nanoplatelets. (Nature Communications | (2020) 11:1285 | https://doi.org/10.1038/s41467-020-14838-4). 

139La NMR detection of Polarons in the Strong Electron Correlated System La0.67Ca0.33MnO3: 139La NMR in the temperature range 3K-900K together with sub-Angstrom resolved TEM, enabled the detection of freezing polarons and discovery of a low-T quantum liquid-crystal phase. (npj Quantum Materials|(2018) 3:20 | https://doi.org/10.1038/s41535-018-0093-4.

The group also acquires unique expertise in the construction of broadband NMR spectrometers. Currently four NMR spectrometers have been constructed operating in the frequency range 2 MHz – 800 MHz, attached to four superconductive magnets (100 MHz, 200 MHz (two), and 400 MHz). Experiments are performed in the temperature range 2K – 1000K.

Photo of the Lab: (Left): Two of the four NMR spectrometers operating at 200 MHz and 400 MHz. (Right): Closer view of the 400 MHz NMR spectrometer.