The layer’s parameters:
Fill 0%Blending Options>Gradient Overlay
Gradient’s parameters: 
Make a copy of the new made layer and apply the previous tool (
Delete Anchior Point Tool) to erase by top from each corner on the right side. Select the
Free Transform option to move a little the right side to the left one:


The layer’s parameters:
Fill 0%Blending Options>Gradient Overlay
Gradient’s parameters: