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

SN - 0921-4526

VL - 340-342

SP - 630

EP - 636

JO - Physica B: Condensed Matter

JF - Physica B: Condensed Matter

T2 - Proceedings of the 22nd International Conference on Defects in (ICDS-22)

Y2 - 28 July 2003 through 1 August 2003

ER -