Asymmetry of the Hamiltonian and the Tolman's length

Using the canonical transformation of the order parameter which restores the Ising symmetry of the Hamiltonian we derive the expression for the Tolman length as a sum of two terms. One of them is the term generated by the fluctuations of the order parameter the other one is due to the entropy. The leading singular behavior of the Tolman length near the critical point is analyzed. The obtained results are in correspondence with that of M.A. Anisimov, Phys. Rev. Lett., \textbf{98} 035702 (2007).