diff --git a/soc/sigma_AHC.f90 b/soc/sigma_AHC.f90
index 07d17b67..02d756b0 100644
--- a/soc/sigma_AHC.f90
+++ b/soc/sigma_AHC.f90
@@ -195,7 +195,7 @@ subroutine sigma_AHC
      outfileindex= outfileindex+ 1
      if (cpuid.eq.0) then
         open(unit=outfileindex, file='sigma_ahe.txt')
-        write(outfileindex, '("#",20a16)')'Conductivity in unit of (Ohm*cm)^-1'
+        write(outfileindex, '("#",a)')'Conductivity in unit of (Ohm*cm)^-1'
         write(outfileindex, '("#",20a16)')'E(eV)', 'xx', 'xy', 'xz', 'yx', 'yy', 'yz', 'zx', 'zy','zz'
         do ie=1, OmegaNum
            write(outfileindex, '(200f16.8)')energy(ie), ((sigma_tensor_ahc(i, j, ie), i=1, 3), j=1, 3)