# Tag Info

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### Does the spin polarised DFT calculation mean broken time reversal symmetry?

Yes, broken symmetry solutions do break time-reversal symmetry, and that's one of the reasons why they are unphysical when the total magnetic moment of the system is 0 (although they are physical when ...
Accepted

### Why can't we change the spin angular momentum of electrons with an external optical field?

This has already been asked in several forms in Physics Stack Exchange. Within the semi-classical 'electric dipole' approximation, only the electric field of light interacts with the electron. The ...

### Spin polarized calculation gives different solution in SIESTA and Quantum ESPRESSO

When running spin polarized calculations with SIESTA, the logical keyword DM.InitSpin.AF will define the initial magnetization. From the SIESTA manual (v4.1.5): DM....

### How to obtain spin projected band structure for system with Spin Orbit Coupling?

Phil's answer is absolutely correct. In non-collinear spinor calculation The spin for each state (at a specific k-point and specific band) can points towards different direction. However, since spin ...

### How to obtain spin projected band structure for system with Spin Orbit Coupling?

Non-collinear spin doesn't mean there's no "up" and "down", it means that the natural quantisation axis (which defines "up" and "down") can vary in space. In ...

### Spin orbit coupling from spin polarized density of states?

I'll try to be as basic as I can in regard to explaining the stuff youve posted. From what I read online, spin-orbit coupling is how the angular momentum of an electron w.r.t. the nucleus interacts ...
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### Why does the S squared value have no meaning in Density Functional Theory?

The Kohn-Sham wavefunction is the wavefunction of a hypothetical system where: (1) there is no interaction between the electrons, (2) the electrons are subject to a repulsive potential (the Hartree-...

### Why can't we change the spin angular momentum of electrons with an external optical field?

well, you certainly can change the spin of an electron through acting on its orbital motion with the electric field. It is called "spin-orbit coupling" (SOC) and a lot of magneto-optical and ...

### Why can't DFT calculate the accurate electronic configuration of the Oxygen atom?

I am unfamiliar with this exact tutorial but this looks fine to me, you have 4 electrons in one spin and 2 in the other, giving a net 2 unpaired electrons. This is correct when you look at the ground ...

### Why can't we change the spin angular momentum of electrons with an external optical field?

I think the claim assumes linear polarization of the light which has zero angular momentum. For circularly polarized light, the spin of the electron should be flipped. (e.g. Appl. Phys. Lett. 114, ...

### How to choose starting magnetization while doing spin polarised calculation in Quantum ESPRESSO?

Is this the wrong assumption I am using for initializing starting_magnetization? If yes, What should be the right fact for choosing the initialization value? The initial magnetization is not so ...

### Spin orbit coupling from spin polarized density of states?

What is spin-orbit coupling (soc) and what does soc strength mean? The spin-orbital coupling (SOC) is a relativistic effect. Mathematically, it can be represented as: $$\vec{L} \cdot \vec{S}$$ in ...

### How do I get exact percentage of spin-polarization in Quantum ESPRESSO?

The estimate of the net electronic spin polarization is calculated using the up and down DOS values at the Fermi level using the following expression: \mathrm{Spin \ polarization}= \frac{ABS(DOS_{UP}...

### How can I obtain seperate spin-up and spin-down bands while considering Spin Orbit Coupling in Quantum ESPRESSO?

If you are considering SOC, which means the noncolinear calculations are performed. I assume that the eigenstate of the Kohn-Sham equation is labeled by $|atom, k, orbital, spin \rangle$. To obtain a ...

### How to change the magnetization direction in Quantum ESPRESSO?

This should be possible. You should impose noncollin = .true., then constrained_magnetization = 'atomic direction'. Finally with ...