“…In this application, the magnetic field is negligible which results in π ππ being defined as unity or one. Equation ( 5) is also known as the Maxwell stress tensor [14,15]. When i = j, the three orthogonal directions that were discussed in the introduction, namely <110>, <111> and <112>, will be given by the matrix elements π 11 , π 22 and π 33 , respectively and are called the electric susceptibilities π ππ for lithiated silicon.…”