@techreport{oai:kanazawa-u.repo.nii.ac.jp:00011972, month = {May}, note = {Gallium nitride (GaN) is a wide-band gap (Eg=3.4eV) semiconductor and is a candi-date for high-power devices. As an impurity, hydrogen (H) plays an important role in GaN-based devices. We perform first-principles calculations to investigate the stable geometry of H impurity. We carry out the density-functional calculations within the generalized gradient approximation (GGA) using PHASE/0. We find that the bond-center site is the most stable site for H+, whereas the trigonal channel at the center of wurtzite, where the hydrogen has three nearest Ga atoms, is the most stable for H0 and H−, which is consistent with the results of past theoretical studies. We discuss some details of optimized geometries and find that these geometries does not contradict with the results of µSR. We confirm that the present supercell model well describes the impurity state and conclude that the hydrogen impurity has a negative-U property in GaN, which is consistent with the past theoretical studies, Selected Papers from the International Symposium on Computational Science - International Symposium on Computational Science Kanazawa University, Japan}, title = {First-principles Study of Hydrogen Impurity in GaN}, year = {2015} }