Fig. 4: DFT analysis of the 125Te NMR Knight shifts in Bi2Te3 nanoplatelets.
From: Resolving Dirac electrons with broadband high-resolution NMR
a Calculated 125Te orbital (green), Fermi contact (red), and dipolar terms (light yellow) of the Knight shift of bulk Bi2Te3 (SOC is set on). The inset shows the temperature dependence of the Knight shift according to experimental data in ref. 14. b The Te(1) and Te(2) DOS at the Fermi level N(EF), across a 9-quintuplet (∼9 nm) Bi2Te3 slab. The gray-shaded area marks a central region in the slab with “bulk-like” character, i.e. significant drop of the DOS. c Calculated 125Te Knight shift of a 5-quintuplet Bi2Te3 slab (SOC is set on). d Simulation of the 125Te NMR signal of a 9-quintuplet slab, by combining calculated bulk and edge state Knight shifts. The bulk/edge intensity ratio was set according to the number of Te sites in in the central (gray-shaded) and edge areas in panel b. Calculated NMR lines were convoluted with a Gaussian function. e The experimental isotropic 125Te NMR spectrum of the Bi2Te3 nanoplatelets. The NMR signal from the edge states at −452 ppm was corrected to account for differential \(T_2^\prime\) signal dephasing.
