Hello,
check the coordinates of the point in cartesian axes (just multiply the
points in crystal axes by the matrix of the inverse lattice) and check
the length of each segment of the path. It is likely that the fourth on
is much longer than the others. I recommend using a number of points
proportional to the length of each segment. This can be done in 3 lines
in gnu/octave (or matlab, if you like the bling)
k=[0.821428571428571 0.339285714285
0.0 0.0 0.0
0.5 0.5 0.5
0.5 0.0 0.5
0.0 0.0 0.0
0.5 0.0 0.0
]
b=[ 2.281217 -1.317061 0.344551
0.000000 2.634122 0.344551
-2.281217 -1.317061 0.344551]
kk=k*b
norm(kk(1:4,:)-kk(2:5,:),2,"rows")
Of course, it would be better if the code worked in every case, but even
the best algorithm to spot high-symmetry points breaks down with some a
sufficiently extreme case.
On 1/17/19 7:15 PM, Vasilios Passias wrote:
Hello. After running a band calculation for Bismuth Selenide, I
encountered a problem with the high symmetry points: two distinct high
symmetry points, K and \Gamma, have the same x-coordinate value (i.e.
the value on the horizontal axis on bandstructure plot) :
image.png
The k-space path I used was Γ→A→Γ→K→M. I have the band input here:
/&control/
/ calculation = 'bands',/
/ restart_mode = 'from_scratch',/
/ pseudo_dir = '/home/passias2/qe-6.3/pseudo/',/
///
/&system/
/ ibrav = 4,/
/ celldm(1) = 7.81969,/
/ celldm(3) = 6.92122,/
/ nat = 15,/
/ ntyp = 2,/
/ ecutwfc = 300.0,/
/ ecutrho = 1200.0,/
/ nbnd = 130/
///
/&electrons/
/ conv_thr = 1.0d-8,/
/ mixing_beta = 0.1/
///
/ATOMIC_SPECIES/
/ Bi 208.980 Bi.pbe-dn-kjpaw_psl.1.0.0.UPF/
/ Se 78.971 Se.pbe-n-kjpaw_psl.0.2.UPF/
/
/
/ATOMIC_POSITIONS crystal/
/ Se 0.00 0.00 0.00/
/ Bi 0.333333 0.666667 0.066/
/ Se 0.666667 0.333333 0.127/
/ Se 0.00 0.00 0.206/
/ Bi 0.333333 0.666667 0.267/
/ Se 0.666667 0.333333 0.333/
/ Bi 0.00 0.00 0.399/
/ Se 0.333333 0.666667 0.46/
/ Se 0.666667 0.333333 0.539/
/ Bi 0.00 0.00 0.6/
/ Se 0.333333 0.666667 0.666/
/ Bi 0.666667 0.333333 0.732/
/ Se 0.00 0.00 0.793/
/ Se 0.333333 0.666667 0.872/
/ Bi 0.666667 0.333333 0.933/
/
/
/K_POINTS crystal_b/
/ 5/
/ 0.0 0.0 0.0 30/
/ 0.0 0.0 0.5 30/
/ 0.0 0.0 0.0 30/
/ 0.66667 -0.3333 0.0 30/
/ 0.5 0.0 0.0 30/
/
/
Could this error be from choosing a point outside of the irreducible
Brillouin zone?
Thank you for your time.
/
/
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--
Lorenzo Paulatto - Paris
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