Computational Modelling — 2D Single-Layer π-Conjugated Nickel Bis(dithiolene) Complex: A Good-Electron-Poor-Phonon Thermoelectric Material

6 measurement groups · 33 results

Reported values remain attached to the sample, method, conditions, extraction quality and source location that produced them.

DFT/DFPT using PBE and PBE0; Quantum ESPRESSO PHONON and EPW/Wannier interpolation

Density functional theory

perfect monolayer MoS2 model · Model

80 Ry cutoff; 12 x 12 x 1 Brillouin-zone mesh; 8 angstrom vacuum; relaxed to 1 meV atom^-1 and 5 meV angstrom^-1 convergence.

Atmosphere: vacuum model
Geometry: 2D periodic monolayer
Context: pristine model comparator
Measurement source: 8 · 4. Experimental Section

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
optimised in-plane lattice constant	3.19 angstrom	—	—	Text Exact Reported	2 · 2.1 Electronic Structure and Phonon Modes
PBE0 bandgap	2.69 eV	—	—	Text Exact Reported	2 · 2.1 Electronic Structure and Phonon Modes
PBE bandgap	1.61 eV	—	—	Text Exact Reported	2 · 2.1 Electronic Structure and Phonon Modes

DFT/DFPT using PBE and PBE0; Quantum ESPRESSO PHONON and EPW/Wannier interpolation

Density functional theory

perfect monolayer (NiC4S4)n model nanosheet · Model

80 Ry cutoff; 4 x 4 x 1 Brillouin-zone mesh; 8 angstrom vacuum; relaxed to 1 meV atom^-1 and 5 meV angstrom^-1 convergence.

Atmosphere: vacuum model
Geometry: 2D periodic monolayer
Context: pristine model system
Measurement source: 8 · 4. Experimental Section

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
highest phonon energy	170 meV (1374 cm^-1)	1374 cm^-1	—	Caption Exact Reported	3 · 2.1 Electronic Structure and Phonon Modes · Figure 1d
optimised in-plane lattice constant	14.63 angstrom	—	—	Text Exact Reported	2 · 2.1 Electronic Structure and Phonon Modes
PBE0 bandgap	0.67 eV	—	—	Text Exact Reported	2 · 2.1 Electronic Structure and Phonon Modes
PBE bandgap	0.11 eV	—	—	Text Exact Reported	2 · 2.1 Electronic Structure and Phonon Modes
imaginary phonon frequencies	no imaginary phonon frequency	—	—	Qualitative Qualitative	2 · 2.1 Electronic Structure and Phonon Modes · Figure 1d

first-principles electron-phonon coupling, Fan-Migdal self-energy, EPW/Wannier interpolation

perfect monolayer MoS2 model · Model

Fröhlich contribution treated by Monte Carlo importance sampling around zone centre; 2402 random q points; remaining contribution on 300^2 q grid.

Atmosphere: vacuum model
Geometry: 2D periodic monolayer
Context: pristine model comparator
Measurement source: 8 · 4. Experimental Section · Equations 1-3, 6; Figure S2

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
acoustic phonon contribution to electron scattering rate	9.3 ps^-1	—	—	Text Exact Reported	3 · 2.2 Electron-Phonon Scattering · Figure S2
electron effective mass at CBM	0.37 me	—	—	Text Exact Reported	3 · 2.2 Electron-Phonon Scattering · Figure 2a
near-CBM quasiparticle lifetime	about 55 fs near the lowest plotted QP energy	—	visual estimate from plotted curve	Visual Estimate Approximate	4 · 2.2 Electron-Phonon Scattering · Figure 2a
optical phonon contribution to electron scattering rate	1.3 ps^-1	—	—	Text Exact Reported	3 · 2.2 Electron-Phonon Scattering · Figure S2
total electron scattering rate at CBM	10.6 ps^-1	—	—	Text Exact Reported	3 · 2.2 Electron-Phonon Scattering · Figure S2

first-principles electron-phonon coupling, Fan-Migdal self-energy, EPW/Wannier interpolation

perfect monolayer (NiC4S4)n model nanosheet · Model

Fröhlich contribution treated by Monte Carlo importance sampling around zone centre; 120 random q points; remaining contribution on 90^2 q grid.

Atmosphere: vacuum model
Geometry: 2D periodic monolayer
Context: pristine model system
Measurement source: 8 · 4. Experimental Section · Equations 1-3, 6; Figure 2

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
acoustic phonon contribution to electron scattering rate	0.77 ps^-1	—	—	Text Exact Reported	3 · 2.2 Electron-Phonon Scattering · Figure 2b
electron effective mass at CBM	0.17 me	—	—	Text Exact Reported	3 · 2.2 Electron-Phonon Scattering · Figure 2a
near-CBM quasiparticle lifetime	about 220 fs near the lowest plotted QP energy	—	visual estimate from plotted curve	Visual Estimate Approximate	4 · 2.2 Electron-Phonon Scattering · Figure 2a
optical phonon contribution to electron scattering rate	3.2 ps^-1	—	—	Text Exact Reported	3 · 2.2 Electron-Phonon Scattering · Figure 2b
net CBM energy change under 0.5% in-plane dilation	total decrease around 3.7 meV	—	around	Text Approximate	4 · 2.2 Electron-Phonon Scattering · Table 1
total electron scattering rate at CBM	4 ps^-1	—	—	Text Exact Reported	3 · 2.2 Electron-Phonon Scattering · Figure 2b
S1-Ni contribution to CBM energy shift under 0.5% strain	-0.45 meV	—	—	Table Exact Reported	5 · 2.2 Electron-Phonon Scattering · Table 1
S1-Ni interatomic distance R0	2.135 angstrom	—	—	Table Exact Reported	5 · 2.2 Electron-Phonon Scattering · Table 1
S1-S2 contribution to CBM energy shift under 0.5% strain	-2.27 meV	—	—	Table Exact Reported	5 · 2.2 Electron-Phonon Scattering · Table 1
S1-S2 interatomic distance R0	3.069 angstrom	—	—	Table Exact Reported	5 · 2.2 Electron-Phonon Scattering · Table 1
S1-S3 contribution to CBM energy shift under 0.5% strain	6.39 meV	—	—	Table Exact Reported	5 · 2.2 Electron-Phonon Scattering · Table 1
S1-S3 interatomic distance R0	3.208 angstrom	—	—	Table Exact Reported	5 · 2.2 Electron-Phonon Scattering · Table 1
S1-S4 contribution to CBM energy shift under 0.5% strain	-7.34 meV	—	—	Table Exact Reported	5 · 2.2 Electron-Phonon Scattering · Table 1
S1-S4 interatomic distance R0	2.968 angstrom	—	—	Table Exact Reported	5 · 2.2 Electron-Phonon Scattering · Table 1

non-equilibrium molecular dynamics using LAMMPS and COMPASS force field

Molecular dynamics

perfect monolayer (NiC4S4)n model nanosheet · Model

NVT relaxation/equilibration at 300 K for 2.5 ns; 0.25 fs timestep; square-like supercells 6 x 7, 8 x 10, 12 x 8, 16 x 25, 22 x 38; each NEMD simulation lasted 25 ns.

Temperature: 300
Atmosphere: vacuum model
Geometry: orthorhombic supercells of transformed 2D (NiC4S4)n; heat transport along x, periodic y and z
Context: pristine model system
Measurement source: 4 · Non-equilibrium molecular dynamics (MD) simulation of lattice thermal conductivity · Figures S5-S6

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
NVT relaxation and equilibration time	2.5 ns at 300 K	—	—	Text Exact Reported	4 · Non-equilibrium molecular dynamics (MD) simulation of lattice thermal conductivity
linear extrapolation coefficient of determination	R^2 = 0.987	—	—	Text Exact Reported	5 · Non-equilibrium molecular dynamics (MD) simulation of lattice thermal conductivity · Figure S6
NEMD production simulation duration	25 ns	—	—	Text Exact Reported	4 · Non-equilibrium molecular dynamics (MD) simulation of lattice thermal conductivity
NEMD timestep	0.25 fs	—	—	Text Exact Reported	4 · Non-equilibrium molecular dynamics (MD) simulation of lattice thermal conductivity
lattice thermal conductivityMarked as a best value within this paper	2.05 W m^-1 K^-1 at 300 K	—	—	Text Exact Reported	5 · Non-equilibrium molecular dynamics (MD) simulation of lattice thermal conductivity · Figure S6

Thomas-Fermi screened charged impurity approximation

perfect monolayer (NiC4S4)n model nanosheet · Model

Screened Coulomb impurity scattering in 2D materials compared with bare Coulomb impurity.

Atmosphere: vacuum model
Geometry: 2D monolayer
Context: impurity-scattering model
Measurement source: 2 · Thomas-Fermi screened charged impurity · Figure S1

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Thomas-Fermi screened impurity scattering strength	much weaker than bare Coulomb impurity	—	—	Qualitative Qualitative	2 · Thomas-Fermi screened charged impurity · Figure S1