Add example Co6Nb4Os2

examples/03_spin_polarized/04_Co6Nb4Os2/INPUT

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+INPUT_PARAMETERS
+
+calculation         scf
+basis_type          lcao
+nspin               2
+symmetry            1
+gamma_only          0
+
+ecutwfc             60
+scf_thr             1e-06
+scf_nmax            100
+
+ks_solver           genelpa
+smearing_method     gaussian
+smearing_sigma      0.005
+
+mixing_type         broyden
+mixing_beta         0.2
+mixing_beta_mag     0.2
+
+out_mul             1
+out_chg             0
+#out_hsr_npz        1
+#out_dm_npz         1
+
+pseudo_dir          ../../../tests/PP_ORB/
+orbital_dir         ../../../tests/PP_ORB/

examples/03_spin_polarized/04_Co6Nb4Os2/KPT

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+K_POINTS
+0
+Gamma
+5  5  2  1 1 1

examples/03_spin_polarized/04_Co6Nb4Os2/README.md

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+# Co6Nb4Os2 Spin-Polarized Calculation Example
+
+This example demonstrates a spin-polarized DFT calculation for the Co6Nb4Os2 compound.
+
+## Special Note: Sensitivity to Smearing Parameter
+
+This calculation is **extremely sensitive to the smearing parameter** (`smearing_sigma`). The total magnetic moment shows significant variation depending on the smearing value:
+
+| smearing_sigma (Ry) | Total Magnetism (μB) |
+|---------------------|----------------------|
+| 0.002               | ~2.20                |
+| 0.005               | ~1.94                |
+| 0.010               | ~0.60                |
+| 0.020               | ~0.00 (non-magnetic) |
+
+### Explanation
+
+The Co6Nb4Os2 system exhibits a delicate balance between magnetic and non-magnetic states. The smearing parameter controls the width of the Gaussian smearing used for occupation numbers, which significantly affects the electronic structure near the Fermi level. For this compound:
+
+- **Small smearing values** (e.g., 0.002 Ry) preserve the magnetic ordering, resulting in a total magnetic moment of ~2.20 μB
+- **Increasing smearing** progressively suppresses the magnetic moment
+- **Large smearing values** (e.g., 0.02 Ry) completely quench the magnetism, leading to a non-magnetic ground state
+
+### Recommended Settings
+
+The default `smearing_sigma` in `INPUT` is set to **0.001 Ry**, which should yield a magnetic moment close to 2.20 μB. Users are advised to carefully test different smearing values when studying this system.
+
+## System Details
+
+- **Composition**: Co6Nb4Os2
+- **Structure**: Hexagonal lattice
+- **Spin polarization**: Enabled (`nspin = 2`)
+- **Basis type**: LCAO
+
+## Files
+
+- `INPUT`: Main input file with calculation parameters
+- `STRU`: Structure file with atomic positions, initial magnetic moments, and numerical atomic orbital definitions
+- `KPT`: k-point mesh definition
+
+### Numerical Atomic Orbitals (NAO)
+
+The `STRU` file references three numerical atomic orbital files:
+- `Co_gga_9au_60Ry_4s2p2d1f.orb`
+- `Nb_gga_9au_60Ry_4s2p2d1f.orb`
+- `Os_gga_9au_60Ry_4s2p2d1f.orb`
+
+The filename format encodes the following information:
+- `9au`: Orbital cutoff radius (9 atomic units)
+- `60Ry`: Energy cutoff (60 Rydberg)
+- `4s2p2d1f`: Number of orbitals per angular momentum channel (4 s-orbitals, 2 p-orbitals, 2 d-orbitals, 1 f-orbital)
+
+The `ecutwfc` parameter in `INPUT` is set to **60** to match the energy cutoff of the orbital files, ensuring consistency in the calculation.
+
+## Running the Calculation
+
+Execute ABACUS in this directory to perform the spin-polarized SCF calculation. Monitor the output for the total magnetic moment in the final SCF iteration.

examples/03_spin_polarized/04_Co6Nb4Os2/STRU

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+ATOMIC_SPECIES
+Co  58.933194     Co_ONCV_PBE-1.2.upf
+Nb  92.90637      Nb_ONCV_PBE-1.2.upf
+Os  190.23        Os_ONCV_PBE-1.2.upf
+
+NUMERICAL_ORBITAL
+Co_gga_9au_60Ry_4s2p2d1f.orb
+Nb_gga_9au_60Ry_4s2p2d1f.orb
+Os_gga_9au_60Ry_4s2p2d1f.orb
+
+LATTICE_CONSTANT
+1.889726
+
+LATTICE_VECTORS
+4.8297140000   0.0000000000   0.0000000000   
+-2.414854000   4.1826560000   0.0000000000   
+0.0000000000   0.0000000000   8.0678760000   
+
+ATOMIC_POSITIONS
+Direct
+
+Co
+0.0000000000
+6
+0.1712410000   0.8287590000   0.7500000000   1   1   1    magmom 0.298
+0.8287600000   0.6575140000   0.2500000000   1   1   1    magmom 0.282
+0.3424860000   0.1712400000   0.2500000000   1   1   1    magmom 0.314
+0.6575140000   0.8287600000   0.7500000000   1   1   1    magmom 0.314
+0.1712400000   0.3424860000   0.7500000000   1   1   1    magmom 0.282
+0.8287590000   0.1712410000   0.2500000000   1   1   1    magmom 0.298
+Nb
+0.0000000000
+4
+0.6666670000   0.3333330000   0.9274990000   1   1   1    magmom 0.053
+0.3333330000   0.6666670000   0.4274990000   1   1   1    magmom 0.055
+0.6666670000   0.3333330000   0.5725010000   1   1   1    magmom 0.055
+0.3333330000   0.6666670000   0.0725010000   1   1   1    magmom 0.053
+Os
+0.0000000000
+2
+0.0000000000   0.0000000000   0.5000000000   1   1   1    magmom 0.033
+0.0000000000   0.0000000000   0.0000000000   1   1   1    magmom 0.027