GT Advanced Technologies Inc. asked for bankruptcy court permission to shut down its synthetic-sapphire operations, citing terms of a contract with Apple Inc. that it called “oppressive” and “burdensome,” Bloomberg News reported on Friday. GT Advanced, based in Merrimack, N.H., filed for bankruptcy last week, less than a year after announcing an agreement to supply sapphire to Apple. The substance is used to make screens on mobile devices more durable. The company told the court on Friday that it was going through cash too fast and must halt operations in Mesa, Arizona, and Salem, Massachusetts, by Dec. 31, at a cost of 890 jobs.
