  Two-qubit gates between spin qubits are often performed using a rectangular
or an adiabatic exchange interaction pulse resulting in a CZ gate. An
oscillating exchange pulse not only performs a CZ gate, but also enables the
iSWAP gate, which offers more flexibility to perform quantum algorithms. We
provide a detailed description for two-qubit gates using resonant and
off-resonant exchange pulses, give conditions for performing the respective
gates, and compare their performance to the state-of-the-art static
counterpart. We find that for relatively low charge noise the gates still
perform reliably and compare to the conventional CZ gate.
