TechniqueAdvantages Disadvantages ARPES 4 Directly image band structure and gap ∆(k) Requires very pristine surfaces, finite energy resolution SQUID 8Sensitive to the sign change of the gap ∆(k) Requires high-quality tunnel junctions ARSH 6Relatively simple thermodynamic measurement Depends on the presence of magnetic vortices Interpretation is dependent on knowledge of Fermi surface details Raman 3Able to choose specific symmetries under test by choosing polarization orientationsRequires detailed theoretical calculations of response functions for each polarization orientation to interpret data aNLME [13][14][15][16] Directly image gap nodal structure in real-space, not sensitive to near-surface qualityRequires high-Q resonance with circulating currents over a single-domain sample.