Questions tagged [electronic-transport]
Questions about electron transport.
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Transiesta with siesta version 4.1.5 not converging
Good evening everyone,
With previous Transiesta versions, we would not have issues with finding the transport involving graphene. However, this was not the case with the latest version. We tried:
...
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Implemetation of NEGF in TranSIESTA
I have a general query regarding NEGF approach:
In TranSIESTA code, when self-energy of the electrodes is calculated, does it require the coupling elements of the electrode with the central scattering ...
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Effect of carrier concentration on electrical conductivity
As per my understanding, the electrical conductivity of a material can be expected to increase with the increased carrier concentration. However, beyond a certain (extreme) point, the electrical ...
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Variation of Conduction band minimum and valence band maximum with applied strain in semconductors
I have been using the Deformation Potential theory to evaluate the electron scattering rates in nanomaterials. In each case, I was under the impression that the Conduction Band Minimum (CBM) and the ...
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Quantum ESPRESSO vs AMS
Both Quantum ESPRESSO and AMS (Amsterdam Modeling Suite) can be used to perform simulations of the materials and their properties. What are the differences between AMS and Quantum ESPRESSO? Is it ...
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Transport calculations with AMSET package
I am trying to calculate transport properties using the AMSET package (with VASP), to be able to calculate the electron relaxation time.
My system is a monolayer of graphene doped with isoelectronic ...
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Inverse Matrix Calculation
I am working on the charge transport calculation, based on the non-equilibrium green function method, for the Hamiltonian with the non-orthogonal basis. Suppose $H$ and $S$ are the Kohn-Sham ...
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Calculation of charge transport with the Non-Orthogonal basis Hamiltonian based on the Non-Equilibrium Green Function Method
I am thinking about one question. If the Hamiltonian matrix is based on the non-orthogonal basis, how to compute the charge conductance with the non-equilibrium green function (NEGF) method.
Suppose ...
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Post-processing in TBTrans
I would like to write a simple code calculating Conductance and Seebeck coefficients in function of the chemical potential. To do this, I would like to use the equation:
$$L_n(\mu, T)=\frac{2}{h}\int ...
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Figure-of-merit with Transiesta/TBtrans
Would it be possible to calculate the figure-of-merit:
$$ZT =\frac{S^2\sigma}{\kappa}T,\tag{1}$$
with Transiesta and TBTrans?
If not, which other programs can be used? I've only read about Gollum.
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Calculation of Seeback coefficient on Transiesta
From the paper Improvements on non-equilibrium and transport Green function
techniques: The next-generation transiesta, and in particular in figure 10b, an I/V curve is reported. I understand that ...
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I/V curve on Transiesta paper
In the paper 'Improvements on non-equilibrium and transport Green function techniques: The next-generation transiesta and in particular in figure 10b, the I/V curve of a specific model is reported.
...
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Could I simulate the applied voltage on the electrode by adding extra electrons in the system?
I try to use molecular dynamics to simulate the half-reaction of the H2O reduction on the Pt cluster. Is it possible to add extra electrons in the system to simulate the reduction process?
The Pt ...
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Would it be appropriate to use a Van der Waals-DFT approximation in Quantum ESPRESSO to study the properties of my material (p-type semiconductor)?
I want to study the structural, optical, electronic and transport properties of my material that contains Cu atoms using Quantum ESPRESSO. I tried so many approximations but every time I face an issue ...
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Any software that can model eddy currents?
Is there any software on metals that can predicts orbital or induced currents in metals in the presence of a magnetic field or electromagnetic waves?
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How to add the scissor operator in Quantum ESPRESSO input?
I want to calculate the optical, transport and electronic properties of my material. GGA underestimate the bandgap.
I tried GGA+U but the bandgap is still underestimated and also when I tried to use ...
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Why can graphene nanoribbons be safely used as electrdes, despite having a finite band gap?
I was following the following this tutorial.
As far as my understanding goes, one should use bulk-like metallic electrodes to avoid problems with screening and Fermi-level definition.
Can someone ...
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How to set the different left and right electrodes of transiesta？
I am using transiesta, which works when the left and right electrode structures are consistent. Now I want to know how to set up the different left and right electrodes, how I should prepare the ...
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How to locate HOMO-LUMO molecular orbitals in Transmisson and PDOS graphs?
I have done TBtrans calculations using SIESTA (v4.0.2) and plotted transmission, as well as PDOS Vs Energy graphs. I want to know how to locate HOMO-LUMO MOs in those graphs (or) how can I say which ...
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Transiesta warning (Error on inverting X6/C7 with error: 1)
I have run into trouble when I try to do transport calculations in TranSIESTA. I got this message in the output file, before reaching convergence:
...
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Current value changes with contour values in SIESTA
My question is related to the topic solved here: DOS calculation with TBTrans
Here, in the answer, the imaginary contour manipulation is proposed to smooth the DOS. I noticed, however, that doing this ...
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Transiesta electrodes with GNR structures
As far as I understand, it would be better to use metallic electrodes in a Transiesta calculation and avoid the usage of semiconducting electrodes. It should be related to the bad screening of the ...
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Transmittive states plotting in TBTrans
I have been using transiesta and TBTrans to calculate the transmission curves of some materials. Could I theoretically compare the Transmission states with the states in the Density of States and the ...
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DOS calculation with TBTrans
I calculated the Transmission curves and the Density of States using TBTrans. In particular, if I have pristine graphene (just for the sake of the example), I obtain as Transmission curve and DOS ...
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Conductance and Seeback coefficient calculations with tbtrans
Like the title says, in TranSiesta I can easily calculate the transmission curves. I know that it is related to the conductance. However, how can I calculate the conductance with tbtrans?
Moreover, to ...
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Transiesta calculation at non-zero bias
I have followed the transiesta tutorials regarding calculations with different bias. I am now using a similar input for my calculations.
However, I found these input parameters
...
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Transiesta geometry optimization
Reading the transiesta manual, I understand that it would be sufficient to optimize the structure within siesta and then use the result for a transiesta run.
However, I have also read that it would be ...
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How to simulate the electron transfer during OER with AIMD?
I am trying to simulate the electron transfer from adsorbed H2O molecule to the electrode with AIMD. I guess I need to set up an external electric field, so the electron inside the H2O molecule would ...
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Transiesta procedure when relaxing the structure
As the title says, I'm interested in performing Transiesta calculations with a device region that needs to be optimized. I read the slides reported here: https://departments.icmab.es/leem/...
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What is the transiesta+tbtrans procedure?
I have tried to run some calculations on transiesta/tbtrans with a non-zero voltage. I started with a zero voltage calculation and copied the .TSDE file to run a calculation with V=0.25. However, I ...
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Empty orbitals in Transiesta
I have noticed some difficulties in converging Transiesta calculations when including empty orbitals in the basis set, particularly when a non-zero bias is applied.
In particular, I have tried to ...
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When we can justify the response to be hold in terms of symmetry?
In this paper, the authors argue the following response relation
$$j_a=\sigma_{abc}E_bE_c \tag{1}$$
can occur in systems with $\mathcal{P}\mathcal{T}$-symmetry with $\mathcal{T}$ the time-reversal ...
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The relation between applied voltage and band gap in Transport calculation (DFT+NEGF)
Hello Dear StackExchange Comunity,
Based on some interesting papers related to quantum transport calculation (Transiesta published paper...), the voltage applied in the device shifts the Fermi level ...
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How can I get the projected density of states within the Green's function method?
I have this Green's function matrix $G^r= (E \mathbb{I} - \hat{H})^{-1}$ in the $|\textrm{site}\rangle\otimes|\textrm{orbital}\rangle\otimes|\textrm{spin}\rangle$ Hilbert space, and I am curious if ...
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Difference between "electrical" and "electronic"?
I found that people often measure "electrical conductivity", but some may say "electronic conductivity". Can anyone explain the terms "electrical" and "electronic&...
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Is it possible to obtain the current-voltage characteristic for a crystal using the Hartree–Fock (or DFT) calculation? [closed]
In continuation of the question of obtaining an electrical conductivity tensor (ECT) from the “first characteristics”, will my following suggestion be correct? Since a crystal with an applied-to-it ...
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Can the electrical conductivity tensor of a crystal be obtained from a Hartree-Fock calculation?
Let’s assume that a crystal has been calculated by Hartree–Fock (HF) method (or DFT one), i.d., so to speak, the "first characteristics", which are eigenvalues and eigenvectors, as well as ...
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Meaning of Kronecker Product in Transport Theory behind BoltzTrap2
I am somewhat confused by the use of a Kronecker Product in Madsen, Georg K. H. et al. “BoltzTraP2, a program for interpolating band structures and calculating semi-classical transport coefficients.” ...
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Transiesta output through a single gold atom
I am looking for the electron transport study in a single gold atom, like the system of single carbon atom shown in transiesta paper by Nick Papior et al. Computer Physics Communications, 212, 8-24, (...
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Why do both my GGA+U and HSE06 calculations suggest that my material is a semiconductor, when I know it should be a conductor? [closed]
I am considering a material that exhibits metallic properties from the four probe measurements between 50-400K. Its electrical conductivity is about 15-20 S/cm and kept almost unchanged with ...
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Can deformation potential theory be applied to 2D and 1D systems?
I was pointed towards the use of the Deformation Potential (DP) theory to calculate the electron relaxation time in a previous question.
However, I still have a doubt regarding its applicability to 2D ...
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How to implement a Weyl semimetal in tight binding? [closed]
I want to study electronic and thermal transport properties of a Weyl semimetal. Until now, I have used only the continuum model hamiltonian ($H=k⋅σ$). As the continuum model has several limitations, ...
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Are there tools to calculate the electrical conductivity of large (>1000 atom) nanostructures?
Are there any free to use tools which can be used to calculate the electrical conductivity of nanostructured materials. The systems that I am interested in consist of several thousand atoms, and ...
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Validity of estimating electron relaxation time using the smallest cross section of a structure [closed]
I am studying nano-scale constrictions in semiconductor materials. Imagine two nano-particles joined together by a single point of crystalline contact to look like an hour-glass filled with sand. ...
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Mobility and chemical potential
I have been studying the Boltztrap2 software to calculate the thermoelectric properties of materials. However when following the tutorial given, the Seebeck coefficient is plotted against ...
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How to evaluate the electron relaxation time of nanostructures computationally
I am working with Si nanowires using the SIESTA ab initio code and the BoltzTraP2 Boltzmann transport equation solver. However, the output of the BoltzTraP2 code comes per relaxation time (...
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Comments on the electronic relaxation time variation between nanowire configurations
I am studying Si nanowires with different cross sections. In my work, I plan to evaluate the thermoelectric performance variation between different configurations. To achieve this, my current approach ...
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Evaluating Seebeck coefficient using DFT
I am working with semiconductor materials using the SIESTA DFT package. I have tried the BoltzTraP2 software interface with SIESTA, however the results (Seebeck coefficient of MgO and Si) did not ...
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What is signified by the properties of the electronic band structure?
When considering the band structure of two materials or two structures along a specific k path, what exactly is meant by the gradient and the distance between band lines?
Does this show any ...
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Single electron transfer periodic DFT in VASP [closed]
I have the following question: I am currently studying the electrocatalytic $\ce{CO2}$ reduction reaction (CO2RR) on $\ce{Cu}$ materials using periodic DFT calculations and I am using the ...
