14: Linear Sodium Chain Transport properties¶
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Outline: Compare the quantum conductance of a periodic linear chain of Sodium atoms with that of a defected chain
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Directories:
tutorials/tutorial14/periodic
tutorials/tutorial14/defected
Files can be downloaded from here
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Input Files
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Na_chain.scf
Thepwscf
input file for ground state calculation -
Na_chain.nscf
Thepwscf
input file to obtain Bloch states for the conduction states -
Na_chain.pw2wan
Input file forpw2wannier90
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Na_chain.win
Thewannier90
input file
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The periodic system contains two unit cells evenly distributed along the
supercell. Transport calculations are performed using
transport_mode = bulk
and so the resulting quantum conductance
represents that of an infinite periodic chain.
The part of the wannier90
input file that controls the transport part
of the calculation looks like:
transport = true
transport_mode = bulk
tran_read_ht = false
one_dim_axis = x
fermi_energy = -2.7401
tran_win_min = -5.0
tran_win_max = 5.0
tran_energy_step = 0.01
translation_centre_frac = 0.5 0.5 0.5
tran_num_bb = 2
The defected system uses a 13 atom supercell with the central atom
position altered to break symmetry. Setting transport_mode = lcr
with
tell wannier90
to treat the system as an infinite system with the
defect at its centre. The supercell is chosen so that is conforms to the
2c2 geometry (see User Guide for details). Each principal layer is 2
atoms long so that the conductor region contains the defected atom plus
a single atom on either side.
The transport section of the input file contains these key differences:
Descriptions of these and other keywords related to the calculation of transport properties can be found in the User Guide.
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Run
pwscf
andwannier90
for the periodic system. -
Run
pwscf
andwannier90
for the defected system. -
The quantum conductance is written to the files
periodic/Na_chain_qc.dat
and , respectively. Compare the quantum conductance of the periodic (bulk) calculation with the defected (LCR) calculation. Your plot should look like this.