# Bold face the author superscript

I have the following piece of code :

\documentclass[12pt]{article}
\usepackage{newtxtext,newtxmath}
\usepackage{authblk}
\usepackage[margin=1in]{geometry}
\renewcommand{\Authfont}{\bfseries\fontsize{12}{14.4pt}\selectfont}
\renewcommand{\Affilfont}{\normalfont\itshape\fontsize{10}{12}\selectfont}
\renewcommand\Authands{, }

\begin{document}
\title{\textbf{A review of Machine learning techniques}\vspace{0ex}}
\author[a*]{Abc}
\author[b]{Def}
\author[c]{Ghi\vspace{0ex}}
\affil[a,b]{XYZ, \vspace{0ex}}
\affil[c]{UVW\vspace{2ex}}
\date{}
\maketitle
\end{document}


I want to boldface the superscript a* contained in [a*].

How can it be done?

• Can you please complete your code snippet to be compilable? – Kurt Dec 17 '18 at 4:42
• For what it's worth, it's not a good idea to want to render the superscript letters in bold. The superscript letters are not part of the names; making them bold will just confuse your readers. Incidentally, is it really necessary to render the authors' names in bold? Overusing bold-facing quickly comes across as shouting, which isn't appreciated by most readers. – Mico Dec 17 '18 at 5:20
• @Kurt I have updated the question. – Navdeep Dec 17 '18 at 5:41
• @Mico thanks for your valuable comment but still is it possible to boldface the superscripts here. If yes, how can it be done?Thanks. – Navdeep Dec 17 '18 at 5:42
• For sure, if you insist on making the letter "a" next to the author's name bold, you should also make it bold subsequently, when it's a prefix to one or more affiliations. Incidentally, I also don't understand why you'd want to render the authors' name -- or, for that matter, the title -- in bold. To get back to your question: No, I don't know how boldfacing of the superscript letters may be achieved. – Mico Dec 17 '18 at 5:48

If you want to print all superscripts in bold, simply redefine the way superscripts are handled:

\documentclass{article}

\usepackage{newtxtext,newtxmath}
\usepackage{authblk}

\renewcommand{\Authfont}{\bfseries\fontsize{12}{14.4}\selectfont}
\renewcommand{\Affilfont}{\normalfont\itshape\fontsize{10}{12}\selectfont}
\renewcommand\Authands{, }

\makeatletter
% Add \bfseries to author superscript
\renewcommand\AB@authnote[1]{\textsuperscript{\normalfont\bfseries#1}}
\makeatother

\begin{document}

\title{\textbf{A review of Machine learning techniques}\vspace{0ex}}
\author[a*]{Abc}
\author[b]{Def}
\author[c]{Ghi\vspace{0ex}}
\affil[a,b]{XYZ, \vspace{0ex}}
\affil[c]{UVW\vspace{2ex}}
\date{}

\maketitle

\end{document}