Partial charge for spin down in current version appears to be zero for all bands

[AsTonyshment]

Describe the bug

When setting calculation = get_pchg and nspin = 2, it appears that the spin-down component is not being calculated correctly. This results in the partial charge for spin down being zero across all bands. Furthermore, the cube file name of spin-down component is not correctly set, either.

I will work on a fix for this issue.

Expected behavior

No response

To Reproduce

No response

Environment

No response

Additional Context

No response

Task list for Issue attackers (only for developers)

• Verify the issue is not a duplicate.
• Describe the bug.
• Steps to reproduce.
• Expected behavior.
• Error message.
• Environment details.
• Additional context.
• Assign a priority level (low, medium, high, urgent).
• Assign the issue to a team member.
• Label the issue with relevant tags.
• Identify possible related issues.
• Create a unit test or automated test to reproduce the bug (if applicable).
• Fix the bug.
• Test the fix.
• Update documentation (if necessary).
• Close the issue and inform the reporter (if applicable).