Ab initio studies of stepped {100} surfaces of KDP crystals

Potassium dihydrogen phosphate (KH₂PO₄, KDP) crystals have important uses in laser components and are grown in large scale for that purpose. The need for habit control has led to interest in the step-pinning mechanisms that cause growth inhibition of the {100} face. Model systems representing five stepped KDP {100} surfaces are prepared and studied using ab initio quantum methods. Results of Hartree–Fock and density functional theory plane-wave calculations are presented, including estimated energies of ion and column removal for the steps. Steps terminated by phosphate ions are found to be less energetically favorable than their potassium-terminated counterparts. In addition, surface layer removal energies for the {100} face and the potassium-bounded and phosphate-bounded {101} faces are reported. The potassium-bounded {101} face is found to have a greater surface removal energy than the unexpressed phosphate-bounded {101} face. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004