corrected lambda axis labels in fig1

Manuscript/EPAWTFT.tex

@@ -1,6 +1,6 @@
 \documentclass[aps,prb,reprint,noshowkeys,superscriptaddress]{revtex4-1}
 \usepackage{subcaption}
-\usepackage{graphicx,tabularx,array,booktabs,dcolumn,xcolor,microtype,multirow,amscd,amsmath,amssymb,amsfonts,physics,siunitx,mhchem}
+\usepackage{bm,graphicx,tabularx,array,booktabs,dcolumn,xcolor,microtype,multirow,amscd,amsmath,amssymb,amsfonts,physics,siunitx,mhchem}
 \usepackage[utf8]{inputenc}
 \usepackage[T1]{fontenc}
 \usepackage{txfonts}