According to one embodiment, an assembly includes a first member configured to have a first linear expansion coefficient, a second member configured to have a second linear expansion coefficient smaller than the first linear expansion coefficient, a pair of connecting members configured to connect the first member with the second member, and a notch configured to be formed in the second member between the connecting members and configured to reduce a sectional area of the second member on a section perpendicular to a straight line that connects the connecting members.