You were almost there. It can be done as follows.
map.put("orderby", "@created");
map.put("orderby.sort", "desc"); // in case you want it descending
In case you need to check property within a child node, you can provide the relative path to that for the orderby value. For eg., if you are searching for dam:Asset and want to order them based on the jcr:lastModified property of its metadata, then your query would be something similar to this.
map.put("path", "/content/dam/geometrixx");
map.put("type", "dam:Asset");
map.put("orderby","@jcr:content/metadata/jcr:lastModified");
For further learning refer this