Load QPI data using *_phase.txt files

def load_field(path):
    '''Load QPI data using *_phase.txt files'''
    path = pathlib.Path(path)
    phase = load_file(path)
    inten = load_file(path.parent / (path.name[:-10] + "_intensity.txt"))
    ampli = np.sqrt(inten)
    return ampli * np.exp(1j * phase)