No, you should never use landscape fabric under sod, as it will prevent the grass from establishing a healthy root system. Sod needs to send its roots deep into the native soil to anchor itself and find moisture, but the fabric creates an impassable barrier. This forces the roots to stay shallow, making the lawn extremely weak and highly vulnerable to dying during a drought or hot spell.
For weed control before laying sod, it is far better to use a non-persistent herbicide or to sheet mulch with a thin layer of cardboard, which will kill the weeds and then decompose, allowing the new roots to pass through.
