What algorithm does Google Scholar use to order papers in a search?
I believe it uses this 


  "Google Scholar aims to rank documents the way researchers do,
  weighing the full text of each document, where it was published, who
  it was written by, as well as how often and how recently it has been
  cited in other scholarly literature." About google scholar


For more detailed answer, 


  "Google Scholar also strengthens the Matthew Effect: articles with
  many citations will be more likely to be displayed in a top position,
  get more readers and receive more citations, which then consolidate
  their lead over articles that are cited less often." Google Scholar‘s
  Ranking Algorithm: An Introductory Overview