[Re:01] Total DOS (TDOS) and Parial DOS (PDOS)

Posted on : February 06, 2021 (Sat) 09:46:51

by root

It depends on the situation: if you are calculating cases where a single atom is contained in the unit cell, the sum of partial DOS always slightly smaller than the total DOS. This is because total DOS is calculated from the number of the states below each energy and is the sum of all contribution including higher angular momentum components that is not obtained in the partial DOS (partial DOS's are those of angular momentum smaller than l_max and also only the contributions integrated within a muffin-tin or atomic sphere). If you are calculating disordered alloy systems, including an impurity limit, or systems with more than a single atom per unit cell, the sum of partial DOS in many cases exceeds the total DOS and this is quite correct. However, if the weighted sum of the partial DOS is taken, where the weight being proportional to the concentration of atoms within the unit cell, does note exceed the total DOS. Another case you might meet occurs when you have a very peaky structure. It may happen that the peak hight exceeds that of total DOS. This again because the total DOS is calculated from the number of the states below each energy and the DOS is obtained by differentiating it, showing a kind of smearing.