ZnSiN2

Contents

• • Crystal Structures

  • Electronic Band Structure

  • Vibrational Properties

  • Elastic Properties

  • Dielectric Properties

  • Index of Refraction

  • Non-Linear Optical Coefficients

Crystal Structures

Spacegroup: Pna2₁ (or Pbn2₁ with current axes choice)

(NOTE: For the crystal modeling purposes, select the spacegroup as Pbn2₁ )

Point group: C_2v

Lattice constants:

Wyckoff positions:

Electronic band structure.

The lowest band gap is indirect: the VBM is near Y, the CBM at Gamma.

The lowest direct gap is at Gamma-Gamma.

Indirect and gap:

5.44 eV QSGW+0.8Sigma+exciton binding energy + zero-point motion correction [3]

3.60 eV LDA [3]

Direct band gap:

5.66 eV QSGW+0.8Sigma+exciton binding energy + zero-point motion correction [3]

3.84 eV LDA [3]

4.46 eV Expt. absorption [4]

Effective masses[2]:

conduction band minimum:

m_cx=0.30, m_cy=0.47, m_cz=0.21

valence band maximum near Y:

m_vx=0.55, m_vy=0.33, m_vz=1.09

valence band maximum at Gamma splittings and effective masses

Figure 1: Band structure of ZnSiN2 using QSGW method. . From data of ref. [3]

Figure 3: Partial densities of states in ZnSiN2. [3]

Vibrational properties

There are 12 modes of a₂, 11 of a₁, b₁ and b₂ symmetry.

All modes are Raman active. The a₁, b₁, b₂, are IR active and exhibit LO-TO splitting.

The Raman tensors for a1 have xx, yy, zz components, for a₂, xy, for b₁ xz and for b₂ yz components

with x||a, y||b, z||c.

a₁ is IR active for z polarization E||c

b₁ is IR active for x polarization E||a

b₂ is IR active for y polarization E||b

Ref. [2]

Elastic Properties

Bulk moduli and pressure derivative

Elastic stiffness constants C_ij (Mbar=100GPa)

Elastic compliances S_ij (Mbar^-1)

Reference: [6]

Piezo-electric constants and spontaneous polarization (cm^-2)

Reference: [6]

Dielectric Properties.

High-frequency ε^∞and static dielectric constants ε⁰