Yes, LANDAU is a Scrabble word!

Letter values in Scrabble US: L 1, A 1, N 1, D 2, A 1, U 1.

Is it a valid word?

LANDAU is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

Soviet physicist who worked on low temperature physics (1908-1968)
a four-wheel covered carriage with a roof divided into two parts (front and back) that can be let down separately

Also: lev davidovich landau.