TY - JOUR
T1 - First-principles thermodynamics of defects in semiconductors
AU - Sanati, M.
AU - Estreicher, S. K.
N1 - Funding Information:
This work was supported in part by the R.A. Welch Foundation, the National Renewable Energy Laboratory and the Alexander von Humboldt Foundation. Many thanks to Texas Tech's High Performance Computer Center for generous amounts of CPU time.
PY - 2003/12/31
Y1 - 2003/12/31
N2 - Today's first-principles theory of defects in semiconductors focuses on the calculation of the electronic contribution to the energy, for example using density-functional theory in periodic supercells. Although the total zero-point energy is ignored, these calculations lead to reliable total energy differences at T = 0 K. However, the contributions of the vibrational energy become increasingly large as T increases. In this paper, we discuss the calculations from first-principles of the vibrational (Helmholtz) free energy. The calculations are done in supercells (with k = 0) and are based on the normal-mode frequencies obtained from linear response theory. We first show that accurate specific heats and other thermodynamic quantities can be obtained in defect-free Si and GaN supercells. Then, light (H2 and H 2*) and heavy (Cu pairs) impurities are considered, and their total energies computed as function of temperature. In these two cases, the vibrational entropy contributions dominate the changes in total energy differences.
AB - Today's first-principles theory of defects in semiconductors focuses on the calculation of the electronic contribution to the energy, for example using density-functional theory in periodic supercells. Although the total zero-point energy is ignored, these calculations lead to reliable total energy differences at T = 0 K. However, the contributions of the vibrational energy become increasingly large as T increases. In this paper, we discuss the calculations from first-principles of the vibrational (Helmholtz) free energy. The calculations are done in supercells (with k = 0) and are based on the normal-mode frequencies obtained from linear response theory. We first show that accurate specific heats and other thermodynamic quantities can be obtained in defect-free Si and GaN supercells. Then, light (H2 and H 2*) and heavy (Cu pairs) impurities are considered, and their total energies computed as function of temperature. In these two cases, the vibrational entropy contributions dominate the changes in total energy differences.
KW - Free energy
KW - Silicon
KW - Theory
KW - Vibrational entropy
UR - http://www.scopus.com/inward/record.url?scp=0347946821&partnerID=8YFLogxK
U2 - 10.1016/j.physb.2003.09.158
DO - 10.1016/j.physb.2003.09.158
M3 - Conference article
AN - SCOPUS:0347946821
VL - 340-342
SP - 630
EP - 636
JO - Physica B: Condensed Matter
JF - Physica B: Condensed Matter
SN - 0921-4526
Y2 - 28 July 2003 through 1 August 2003
ER -