Matplotlib Plots: Bold font face not working for Helvetica Neue but works fine with Arial

Question

I am having trouble setting the bold face for 'Helvetica Neue' font while using matplotlib plot. It works file with 'Arial' but somehow bold face for 'Helvetica Neue' doesn't work. Any suggestion?

Here the python code I am using:

mpl.rcParams['xtick.labelsize'] = 14
mpl.rcParams['ytick.labelsize'] = 14

mpl.rcParams['font.family'] = 'sans-serif'
#mpl.rcParams['font.sans-serif'] = ['Arial Narrow']
#mpl.rcParams['font.sans-serif'] = ['Arial']
mpl.rcParams['font.sans-serif'] = ['Helvetica Neue']
mpl.rcParams["font.weight"] = "bold"
mpl.rcParams["axes.labelweight"] = "bold"
mpl.rcParams["axes.labelsize"] = 16

params = {'mathtext.default': 'regular'}
plt.rcParams.update(params)

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axes.set_xlabel("hello world")
axes.set_ylabel('hello world  1x10$^{555}$ (unit)')

Here are the attached images:

Answer 1

Managed to get it working finally. Here are the steps I took.

1. Convert the desired .ttc font files to .ttf using the online font converter.

2. Then paste these .ttf converted files into >>

       <python install patl>/python3.9/site-packages/matplotlib/mpl-data/fonts/ttf
   

3. Remove the matplotlib cache (important step to see the changes) using

   rm -rf ~/.matplotlib/fontlist.cache
   

   and

   rm -rf ~/.matplotlib/fontlist.json
   

4. Re-run the same code as in the question. It worked all well!