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<p class="MsoNormal">Dear WIEN2k users,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-GB">I have three questions concerning the inclusion of spin in a material in WIEN2k.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">The three questions concern the two terms where a spin-dependent term appears in the Pauli Hamiltonian for magnetic systems, which are:<br>
<br>
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Question 1)<br>
In the Pauli Hamiltonian a term appears which is a dot product of the spin-matrices of the system and an effective magnetic field.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">The effective magnetic field is a summation of an external magnetic field and an exchange-correlation term. The exchange-correlation term B_xc, is expressed as a derivative of the density w.r.t. the magnetization (in
the LDA framework) and that B_xc is parallel to the magnetization density vector. If I understand correctly then the material of interest is magnetic when B_xc is nonzero.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">When doing a spin-polarized calculation, what happens then to the external magnetic field term? Is the external magnetic field term set to zero?
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Question 2)<br>
The other term in the Pauli Hamiltonian is the spin-orbit coupling (SOC) term, which is proportional to (1/r x dV/dr ) (dV/dr = the derivative of the potential w.r.t. the radial coordinate).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">When doing a calculation including SOC the script init_so asks for the magnetization direction (in hkl).
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">In a non-spin polarized calculation with SOC the magnetization direction has no meaning, is this correct?
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><br>
<br>
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Question 3) <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">If the system of interest is a magnetic system then a spin-polarized calculation with SOC should give me 1) the strength of the magnetization along the chosen magnetization axis, and 2) the spin-up and spin-down density
of states (DOS) along the chosen axis. But a spin-polarized calculation without SOC will not give me the spin-up and spin-down DOS. Is this correct?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Cheers,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Luigi Maduro<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:NL">PhD candidate<br>
Kavli Institute of Nanoscience<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:NL">Department of Quantum Nanoscience<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:NL">Faculty of Applied Sciences<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:NL">Delft University of Technology<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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