Arunava Majumdar, a top Indian-American scientist, is leaving his job at the US energy department as the Senate has not confirmed his elevation as an undersecretary at the department.
President Barack Obama Tuesday withdrew Majumdar's nomination, which was sent to the Senate on Nov 30 last year, a brief White House announcement said.
However, Science journal citing Energy Secretary Steven Chu reported that Majumdar, who has led the energy department's Advanced Research Projects Agency-Energy (ARPA-E) for nearly two-and-a-half years, will leave June 9.
"Under Arun's leadership, we have seen ARPA-E grow from a fledgling programme to become a leading agency for innovation and energy research," Chu wrote to agency staff members in an e-mail last week.
"Arun has recruited some of the most talented professionals across the country to join the ranks at ARPA-E and create programs that have the potential of changing the entire energy landscape."
Majumdar came to Washington from Lawrence Berkeley National Laboratory in California.
"Arun's departure is a kick in the stomach," Barton Gordon, a former member of the US House of Representatives who spearheaded the creation of ARPA-E in 2007, was quoted as saying.
Gordon, now a lobbyist with K&L Gates in Washington, DC, said Majumdar is a "good scientist and a good organizer who created a good bipartisan following [in Congress] for ARPA-E. I don't think people realised what a good politician he is. He's a what-you-see-is-what-you-get kind of guy."
Modelled after the Pentagon's Defence Advanced Research Projects Agency, ARPA-E is designed to funnel money quickly to high-risk, "transformational" efforts to develop new energy technologies.