Is there a Chinese idiom that involves a "Creator"?
The authors's claim seems likely true.  Of course among the several authors and the editor who passed the article on, some may have had a different idea than others.

Victor Mair at http://languagelog.ldc.upenn.edu/nll/?p=24360 was right to say "no matter what the authors may have meant if they were thinking of a Chinese term, or even if they weren't thinking of a particular Chinese term, paper was written in English for consumption by the international community of scientists, and ... conveys the wrong message for a scientific paper."  Really the paper should not have been printed this way. 

But historically there has been huge debate over how ancient, or classical, or later Chinese, ideas of 天 relate to western religious ideas.  Does 天 mean God, or god, or heaven, or just sky as a metaphor for the grandest most stable aspect of existence?  Even within the 论语/Analects some occurrences seem quite materialistic, so that it would mean overall nature, and others more anthropomorphic suggesting a God with personal intentions.  Many other characters have similar ambiguity and there is every reason to suppose that through history different Chinese people have meant different things by this.

I have not found a source giving the original Chinese from this paper.  But the website http://wap.sciencenet.cn/info.aspx?mod=news&amp;id=339768 discusses this case and offers several idioms, which they claim would not seem religious to most Chinese people but would to many westerners:

相信很多母语为中文的朋友都会理解，“造物主” “神奇的造物主” “上帝之手”……当初赵忠祥在《动物世界》里不都是这么讲的吗？在我们眼里这样的表达和“大自然”无异，也并不会有任何宗教相关的意识和概念。但是当这些东西放到英文环境下，其含义往往会丰富起来。

At first I was not clear on the phrase 赵忠祥, but March Ho's comment led me to find it is the name of the narrator of a TV show  《动物世界》 (Animal World).

Certainly those idioms can be religious in Chinese.  But "上帝" is also used for what some western physicists call the "God Particle"--the Higgs boson, and that is never understood religiously.

Mair goes on to say: 


  Even if they were unaware that "the Creator" — especially when
  capitalized, as it always is in the paper under consideration —
  generally refers to the Judeo-Christian God, at least Le Xiong must
  have been aware that the Latin suffix -or indicates one who performs a
  specified action.  Thus "the Creator" (not "a creator") is a very
  different proposition from "creation".


But within the English language many creationists say just as indignantly that everyone should know the suffix "tion" in words like option, election, creation, indicates that someone has opted, or elected, or created something, so they insist "Creator" is not a different proposition from "creation."  I am not willing to blame the authors for ignoring Latin etymology.

As to the article, yes it should not have appeared this way.  As to what the authors meant, as Stan well says,  the authors don't believe in creationism, and they didn't mean it.