Shimano, R. & Tsuji, N. Higgs mode in superconductors. Annu. Rev. Condens. Matter Phys. 11, 103–124 (2020).
Tinkham, M. Introduction to Superconductivity (Dover Publications, 1996).
Bardeen, J., Cooper, L. N. & Schrieffer, J. R. Theory of superconductivity. Phys. Rev. 108, 1175–1204 (1957).
Lee, P. A., Nagaosa, N. & Wen, X.-G. Doping a Mott insulator: physics of high-temperature superconductivity. Rev. Mod. Phys. 78, 17–85 (2006).
Orenstein, J. & Millis, A. J. Advances in the physics of high-temperature superconductivity. Science 288, 468–474 (2000).
Basov, D. N. & Timusk, T. Electrodynamics of high-Tc superconductors. Rev. Mod. Phys. 77, 721–779 (2005).
Tachiki, M., Koyama, T. & Takahashi, S. Electromagnetic phenomena related to a low-frequency plasma in cuprate superconductors. Phys. Rev. B 50, 7065–7084 (1994).
Tamasaku, K., Nakamura, Y. & Uchida, S. Charge dynamics across the CuO2 planes in La2−xSrxCuO4. Phys. Rev. Lett. 69, 1455–1458 (1992).
Kadowaki, K. et al. Longitudinal Josephson-plasma excitation in Bi2Sr2CaCu2O8+δ: direct observation of the Nambu-Goldstone mode in a superconductor. Phys. Rev. B 56, 5617–5621 (1997).
Corson, J., Orenstein, J., Oh, S., O’Donnell, J. & Eckstein, J. N. Nodal quasiparticle lifetime in the superconducting state of Bi2Sr2CaCu2O8+δ. Phys. Rev. Lett. 85, 2569–2572 (2000).
Higgs, P. W. Broken symmetries, massless particles and gauge fields. Phys. Rev. Lett. 12, 132–133 (1964).
Nambu, Y. Energy gap, mass gap, and spontaneous symmetry breaking. Int. J. Mod. Phys. A 25, 4141–4148 (2010).
Pekker, D. & Varma, C. M. Amplitude/Higgs modes in condensed matter physics. Annu. Rev. Condens. Matter Phys. 6, 269–297 (2015).
Volkov, A. F. & Kogan, S. M. Collisionless relaxation of the energy gap in superconductors. Zh. Eksp. Teor. Fiz. 65, 2038–2046 (1973).
Matsunaga, R. et al. Higgs amplitude mode in the BCS superconductors Nb1−xTixN induced by terahertz pulse excitation. Phys. Rev. Lett. 111, 057002 (2013).
Katsumi, K. et al. Higgs mode in the d-wave superconductor Bi2Sr2CaCu2O8+x driven by an intense terahertz pulse. Phys. Rev. Lett. 120, 117001 (2018).
Nambu, Y. Quasi-particles and gauge invariance in the theory of superconductivity. Phys. Rev. 117, 648–663 (1960).
Anderson, P. W. Plasmons, gauge invariance, and mass. Phys. Rev. 130, 439–442 (1963).
Higgs, P. W. Broken symmetries and the masses of gauge bosons. Phys. Rev. Lett. 13, 508–509 (1964).
Fertig, H. A. & Das Sarma, S. Collective modes in layered superconductors. Phys. Rev. Lett. 65, 1482–1485 (1990).
Economou, E. N. Surface plasmons in thin films. Phys. Rev. 182, 539–554 (1969).
Sun, Z., Fogler, M. M., Basov, D. N. & Millis, A. J. Collective modes and terahertz near-field response of superconductors. Phys. Rev. Res. 2, 023413 (2020).
Richards, D., Zayats, A., Keilmann, F. & Hillenbrand, R. Near-field microscopy by elastic light scattering from a tip. Philos. Trans. R. Soc. A 362, 787–805 (2004).
Chen, J. et al. Optical nano-imaging of gate-tunable graphene plasmons. Nature 487, 77–81 (2012).
Fei, Z. et al. Gate-tuning of graphene plasmons revealed by infrared nano-imaging. Nature 487, 82–85 (2012).
Leitenstorfer, A. et al. The 2023 terahertz science and technology roadmap. J. Phys. D Appl. Phys. 56, 223001 (2023).
Dunmore, F. J. et al. Observation of below-gap plasmon excitations in superconducting YBa2Cu3O7 films. Phys. Rev. B 52, R731–R734 (1995).
Stiewe, F.-F. et al. Spintronic emitters for super-resolution in THz-spectral imaging. Appl. Phys. Lett. 120, 032406 (2022).
Handa, T. et al. Terahertz emission from giant optical rectification in a van der Waals material. Nat. Mater. 24, 1203–1208 (2025).
Blanchard, F. et al. Real-time terahertz near-field microscope. Opt. Express 19, 8277–8284 (2011).
Chen, S.-C. et al. Ghost spintronic THz-emitter-array microscope. Light Sci. Appl. 9, 99 (2020).
Yu, Y. et al. High-temperature superconductivity in monolayer Bi2Sr2CaCu2O8+δ. Nature 575, 156–163 (2019).
Mitra, S., Avazpour, L. & Knezevic, I. Terahertz conductivity of two-dimensional materials: a review. J. Phys. Condens. Matter 37, 133005 (2025).
Seifert, T. et al. Efficient metallic spintronic emitters of ultrabroadband terahertz radiation. Nat. Photonics 10, 483–488 (2016).
Born, M. & Wolf, E. Principles of Optics: Electromagnetic Theory of Propagation, Interference and Diffraction of Light (Cambridge Univ. Press, 1999).
Michael, M. H. et al. Resolving self-cavity effects in two-dimensional quantum materials. Preprint at https://doi.org/10.48550/arXiv.2505.12799 (2025).
Dressel, M. & Grüner, G. Electrodynamics of Solids: Optical Properties of Electrons in Matter (Cambridge Univ. Press, 2002).
Kaindl, R. A., Carnahan, M. A., Chemla, D. S., Oh, S. & Eckstein, J. N. Dynamics of Cooper pair formation in Bi2Sr2CaCu2O8+δ. Phys. Rev. B 72, 060510 (2005).
Cocker, T. L. et al. Microscopic origin of the Drude-Smith model. Phys. Rev. B 96, 205439 (2017).
Molegraaf, H. J. A., Presura, C., van der Marel, D., Kes, P. H. & Li, M. Superconductivity-induced transfer of in-plane spectral weight in Bi2Sr2CaCu2O8+δ. Science 295, 2239–2241 (2002).
Jacobs, T., Sridhar, S., Li, Q., Gu, G. D. & Koshizuka, N. In-plane and c-axis microwave penetration depth of Bi2Sr2CaCu2O8+δ crystals. Phys. Rev. Lett. 75, 4516–4519 (1995).
Corson, J., Mallozzi, R., Orenstein, J., Eckstein, J. N. & Bozovic, I. Vanishing of phase coherence in underdoped Bi2Sr2CaCu2O8+δ. Nature 398, 221–223 (1999).
Kosterlitz, J. M. & Thouless, D. J. Ordering, metastability and phase transitions in two-dimensional systems. J. Phys. C Solid State Phys. 6, 1181 (1973).
Minnhagen, P. The two-dimensional Coulomb gas, vortex unbinding, and superfluid-superconducting films. Rev. Mod. Phys. 59, 1001–1066 (1987).
Lee, W. S. et al. Abrupt onset of a second energy gap at the superconducting transition of underdoped Bi2212. Nature 450, 81–84 (2007).
Pearl, J. Current distribution in superconducting films carrying quantized fluxoids. Appl. Phys. Lett. 5, 65–66 (1964).
Brandt, E. H. Vortex-vortex interaction in thin superconducting films. Phys. Rev. B 79, 134526 (2009).
Banerjee, A. et al. Superfluid stiffness of twisted trilayer graphene superconductors. Nature 638, 93–98 (2025).
Tanaka, M. et al. Superfluid stiffness of magic-angle twisted bilayer graphene. Nature 638, 99–105 (2025).
