QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: ATK-user-zuox on March 7, 2016, 09:42
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Hello,i recently learned the spin density from the http://www.quantumwise.com/documents/tutorials/latest/GrapheneBloch/index.html/electrondensity.spin.html (http://www.quantumwise.com/documents/tutorials/latest/GrapheneBloch/index.html/electrondensity.spin.html),The block state and the band structure is normal ,but when i calculated the spin density difference and visualize it in the view subframe,it turned out that the color and the pattern is not consistent with the the Mulliken populations that the numbers 0 and 1) have a surplus population of 0.25 of either spin-up or spin-down.I read some literatures that the spin density is usually red and blue ,i change the color map ,it still exhibited wrong color.can anyone help me fix it ?
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Looks like you need to tune the max and min values of the visualization in order to see the fine structure of the density difference grid . Use the "Properties" tool to do this.
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I think the basic problem is that you are plotting an isosurface = one single value of the grid. You need to look at the contour plane, which shows all values, encoded by color.
Just a side note also: there is no "wrong color" for plotting anything, red and blue are not universally adopted as representing spin up and down. You can just as well choose yellow and green if you think it illustrates the point you are making better.
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Thanks for your kind suggestion,The updated example of Spin-dependent Bloch states in graphene nanoribbons is in the http://docs.quantumwise.com/tutorials/spin_bloch_gnr.html?highlight=spin%20density (http://docs.quantumwise.com/tutorials/spin_bloch_gnr.html?highlight=spin%20density) .It quickly solved my confusion .As you said ,there is no wrong or right color in my spin density difference plot,all i need to do is to modify the isovalue and choose the appropriate color map to make it look more nice.