@Article{Lahnemann_prb_2012,
  Title                    = {Direct experimental determination of the spontaneous polarization of {GaN}},
  Author                   = {L\"ahnemann, Jonas and Brandt, Oliver and Jahn, Uwe and Pf\"uller, Carsten and Roder, Claudia and Dogan, Pinar and Grosse, Frank and Belabbes, Abderrezak and Bechstedt, Friedhelm and Trampert, Achim and Geelhaar, Lutz},
  Journal                  = {Phys. Rev. B},
  Volume                   = {86},
  Number                   = {8},
  Pages                    = {081302(R)},
  Year                     = {2012},
  Abstract                 = {We present a universal approach for determining the spontaneous polarization Psp of a wurtzite semiconductor from the emission energies of excitons bound to the different types of stacking faults in these crystals. Employing micro-photoluminescence and cathodoluminescence spectroscopy, we observe emission lines from the intrinsic and extrinsic stacking faults in strain-free GaN micro-crystals. By treating the polarization sheet charges associated with these stacking faults as a plate capacitor, Psp can be obtained from the observed transition energies with no additional assumptions. Self-consistent Poisson-Schr\"odinger calculations, aided by the microscopic electrostatic potential computed using density-functional theory, lead to nearly identical values for Psp. Our recommended value for Psp of GaN is$-0.022\pm0.005$~C/m$^2$.},
  Arxiv                    = {1201.4294},
  Doi                      = {10.1103/PhysRevB.86.081302}
}