Theoretical condensed matter physics

Miguel Ángel Sánchez Martínez

Theoretical condensed matter physicist working on topological matter, superconductivity, and experimental signatures.

I am a Postdoctoral Research Associate in Dr. Felix Flicker’s group at the H.H. Wills Physics Laboratory, University of Bristol, funded by the EPSRC grant “Exact Results in Aperiodic Systems”. My work lies at the intersection of topological quantum matter, superconductivity, and aperiodic systems, aiming to connect theory and experiment.

Recent topics: multifold fermions and nonlinear optics, chiral/nematic superconductors and optical probes in TMDs, strong correlations and disorderd metals, and Majorana modes and fractal phase transitions in quasicrystals.

Affiliation: H.H. Wills Physics Laboratory
University of Bristol
Tyndall Avenue, Bristol BS8 1TL, United Kingdom
Email: contact@masanchezmartinez.com
Profiles: Google Scholar ORCID arXiv

Trajectory

2023–Present

Postdoctoral Research Associate, H.H. Wills Physics Laboratory, University of Bristol (Dr. Felix Flicker).
Topic: Topological properties and strong correlations in aperiodic systems. Funded by EPSRC “Exact Results in Aperiodic Systems”.
2022–2023

Postdoctoral Researcher, Donostia International Physics Center (DIPC), San Sebastián (Dr. Fernando de Juan).
Topic: Optical properties and chiral superconductivity in transition metal dichalcogenides.
03–06/2020

Research Intern, Microsoft Station Q, Santa Barbara.
Topic: Charge dynamics of superconducting islands proximity-coupled to metallic leads (Majorana physics).
Supervisor: Dr. Andrey Antipov.
10–12/2019

Industrial Secondment (GreQue PhD Fellowship), Microsoft Station Q, Santa Barbara.
Topic: Localisation of electrons in topological 3D semimetals.
Supervisor: Dr. Andrey Antipov.
2018–2021

PhD in Condensed Matter Physics, Université Grenoble Alpes. Marie Curie fellow (GreQue COFUND) at Néel Institute, CNRS.
Thesis: Linear and nonlinear optical responses of chiral multifold semimetals. Award: Springer Theses (2022).
Supervisors: Dr. Adolfo G. Grushin and Dr. Serge Florens.

Research

My research focuses on various aspects of theoretical condensed matter physics, with a particular emphasis on topological systems and unconventional superconductors. A central part of my work is connecting theory and experiment, with a focus on observables accessible in transport, linear optics, and nonlinear optical experiments. I also have a strong interest in the physics of topological matter in quasicrystals, with a focus on Majorana modes for quantum computing.

Current research directions

Topological matter in quasicrystals: Majorana modes for quantum computing

Emergence of Majorana modes in quasiperiodic systems, such as 1D Kitaev chains with quasicrystalline symmetries. Fractal spectra and topological phase transitions in aperiodic lattices. Higher-order topological quasiparticles in quasicrystalline systems.

Unconventional superconductivity

Optical probes of pairing in superconductors, chiral/nematic order, other optical signatures of unconventional superconductivity charactersing the topological phases₂RuO₄.

Topological quasiparticles in chiral/multifold semimetals

Linear and nonlinear optical response (e.g. SHG), circular photogalvanic effect, and transport/optical fingerprints of multifold fermions (CoSi, RhSi).

News & Blog

Notes on research and non‑research topics.

It took 67 years to discover Pines' demon. Our work shows that it is something even more unusual!

Research Feb 2026

Pines' demon was predicted to exist in 1956, but it took 67 years to discover it in 2023. Our work shows that it is something even more unusual! The first report of this quasiparticle in Sr2RuO4 shows some discrepancies with the acoustic dispersion relation that the demon should follow. Here we show that the demon suffers a universal effect from momentum relaxation: it develops a momentum gap (similar to that of a tachyon!?). Check out the preprint here!: arXiv:2602.02796

Our work on Herbertsmithite is accepted in Nature Physics!

Research Feb 2026

Our work on Herbertsmithite has been accepted in Nature Physics! Check out the preprint here: arXiv:2510.11678

Uncovering the fractal topology of Majoranas in quasicrystals

Research Feb 2026

We recently submitted a paper on the fractal topology of Majoranas in quasicrystals. Some really interesting results! Check it here: arXiv:2602.02796

Using light to test topological superconductivity

Research Feb 2026

Our most recent work on using light to test topological superconductivity has been published in Physical Review B! You can find it here (it's open access!): https://doi.org/10.1103/s1wd-25dz
The code developed for this work is also published in open access in Zenodo, check it here!: https://doi.org/10.5281/zenodo.18436728

Julia Hannukainen's report: all-female speaker line-up in condensed matter

Research Oct 2025

Our colleague Julia Hannukainen has written a fantastic piece on her attendance to the Grete Hermann Network workshop. You can read it here: Meeting report: all-female speaker line-up in condensed matter

Publications

This is a short selection of representative papers. For a complete list, please refer to my profiles on Google Scholar or arXiv.

Superconductivity, strong correlations and collective modes

Momentum-gapped quasiparticles in disordered metals
M. Á. Sánchez‑Martínez, B. Goutéraux, L. Rademaker, F. Flicker.
collective modes Sr₂RuO₄
https://arxiv.org/abs/2603.17002
Spinon mediation of witness‑spin dynamics and ground state in herbertsmithite
H. Takahashi, J. Murphy, M. Wood‑Thanan, P. Puphal, M. Á. Sánchez‑Martínez, F. Jerzembeck, C.C. Hsu, J. Ward, M. Isobe, Y. Matsumoto, H. Takagi, S. Blundell, M. Norman, F. Flicker, J.C. Séamus Davis.
Accepted in Nature Physics (2026). spin liquids herbertsmithite
https://arxiv.org/abs/2510.11678
Optical probes of unconventional pairing states in transition metal dichalcogenides
M. Á. Sánchez‑Martínez, D. Muñoz‑Segovia, F. de Juan.
Physical Review B (2026). superconductivity optics
https://journals.aps.org/prb/accepted/10.1103/s1wd-25dz

Topological quasicrystalline matter

Fractal Topology of Majorana Bound States in Superconducting Quasicrystals
W. Caiger, F. Flicker, M. Á. Sánchez‑Martínez.
arXiv preprint (2026). Majorana fermions superconductivity quasicrystals
https://doi.org/10.48550/arXiv.2602.02796
Giant optical response of multi‑Weyl fermions stabilized by quasicrystalline symmetries
M. Á. Sánchez‑Martínez, I.C. Fulga, D. Varjas, A.G. Grushin, F. Flicker.
In preparation (2026). quasicrystals optics

Topological multifold fermions and nonlinear optics

Second‑harmonic generation in the topological multifold semimetal RhSi
B. Lu, S. Sayyad, M. Á. Sánchez‑Martínez, K. Manna, C. Felser, A.G. Grushin, D. Torchinsky.
Phys. Rev. Research 4, L022022 (2022). SHG multifold fermions
https://doi.org/10.1103/PhysRevResearch.4.L022022
Optical signatures of multifold fermions in the chiral topological semimetal CoSi
B. Xu*, Z. Fang*, M. Á. Sánchez‑Martínez*, J.W.F. Venderbos, Z. Ni, T. Qiu, K. Manna, W. Wang, J. Paglione, C. Bernhard, C. Felser, E.J. Mele, A.G. Grushin, A.M. Rappe, L. Wu.
PNAS 2020, 2010752117 (2020). multifold fermions optics
https://doi.org/10.1073/pnas.2010752117
Linear and nonlinear optical responses in the chiral multifold semimetal RhSi
Z. Ni, B. Xu, M. Á. Sánchez‑Martínez, Y. Zhang, K. Manna, C. Bernhard, J.W.F. Venderbos, F. de Juan, C. Felser, A.G. Grushin, L. Wu.
npj Quantum Materials 5, 96 (2020). nonlinear optics multifold fermions
https://doi.org/10.1038/s41535-020-00187-y
Linear optical conductivity of chiral multifold fermions
M.‑Á. Sánchez‑Martínez, F. de Juan, A.G. Grushin.
Phys. Rev. B 99, 155145 (2019). theory multifold fermions
https://doi.org/10.1103/PhysRevB.99.155145

Other publications

Linear and nonlinear optical responses of chiral multifold semimetals
M. Á. Sánchez‑Martínez.
Springer Theses Series, Springer‑Nature, Cham (2023). book
https://link.springer.com/book/10.1007/978-3-031-25771-1
Spectral and optical properties of Ag₃Au(Se₂,Te₂) and dark matter detection
M.‑Á. Sánchez‑Martínez*, I. Robredo*, A. Bidaurrazaga, A. Bergara, F. de Juan, A.G. Grushin, M.G. Vergniory.
J. Phys. Mater. 3, 014001 (2019). spectral optics
https://doi.org/10.1088/2515-7639/ab3ea2
Impact of the regularization parameter in the mean free path reconstruction method: Nanoscale heat transport and beyond
M.-Á. Sánchez‑Martínez, F. Alzina, J. Oyarzo, C.M. Sotomayor Torres, E. Chavez‑Angel.
Nanomaterials 9, 414 (2019). nanoscale heat phonons
https://doi.org/10.3390/nano9030414

Recent talks and seminars

Selected recent invitations and conference contributions.

Abundance of Majorana modes in quasicrystals (poster by W. Caiger, co‑supervised)
SDIQT25 International Workshop. Salamanca, Spain · Jun 2025.
Unraveling Pines’ demon in Sr₂RuO₄ (invited)
University of Geneva (invited by Prof. Louk Rademaker). Geneva, Switzerland · Jun 2024.
Linear optical response of chiral multifold fermions
NGSCES 2024 International Conference. Girona, Spain · Oct 2024.
Unraveling Pines’ demon in Sr₂RuO₄ (poster)
Electrons, Photons and Plasmons 2024 Workshop. Nyon, Switzerland · Jun 2024.
Unraveling Pines’ demon in Sr₂RuO₄ (oral)
Condensed Matter Physics in the City 2024 · Jun 2024.
Fingerprints of multifold fermions in optics: linear and nonlinear optical responses of CoSi and RhSi (oral)
APS March Meeting 2023, Session M25. Las Vegas, USA · Mar 2023.
Unconventional fermions and where to find them: linear and nonlinear optical responses of CoSi and RhSi (poster)
GEFES 2023 (RSEF). Salamanca, Spain · 2023.
Unconventional fermions and how to find them: optical probes of chiral multifold semimetals (oral)
International Focus Workshop in Topological Materials: From Weak to Strong Correlations. MPIPKS, Dresden, Germany · Apr 2022.
Linear and nonlinear optical responses of chiral multifold semimetals (oral)
APS March Meeting 2022, Session Y59. Chicago, USA · Mar 2022. (MCAA Micro Travel Grant, SCHINEs)
Optical signatures of multifold fermions in chiral topological semimetals RhSi and CoSi (poster)
LEES 2021: Low‑Energy Electrodynamics in Solids. Virtual · Jun–Jul 2021.
Linear and nonlinear optical responses of chiral multifold semimetals (invited)
Nanyang Technological University (invited by Prof. Justin Song). Virtual · Sep 2021.
Optical signatures of multifold fermions in RhSi and CoSi (oral)
APS March Meeting 2021, Session A45. Virtual · Mar 2021.
Linear optical conductivity of the chiral multifold semimetal RhSi (poster)
Dynamics of Emerging Quasiparticles in Topological Dirac Materials (WE‑Heraeus 731). Bad Honnef, Germany · Oct 2020.
Optical conductivity of the multifold semimetal RhSi (poster)
CMD 2020 GEFES (RSEF‑GEFES & EPS‑CMD). Virtual · Aug–Sep 2020.
Charge dynamics of metallic and superconducting islands coupled to metallic leads (oral)
Microsoft Station Q Research Intern Talk. Santa Barbara, USA · Jun 2020.
Blackboard Seminar: Multifold fermions in conventional crystals
Kavli Institute for Theoretical Physics (Spin & Heat Transport in Quantum and Topological Materials program). Santa Barbara, USA · Oct–Dec 2019.
Linear optical response of chiral multifold fermions (poster)
Ultrafast and Nonlinear Dynamics of Quantum Materials. Univ. Paris‑Diderot, France · Jun 2019.
Linear optical response of chiral multifold fermions (oral)
NGSCES 2018 International Conference. Donostia‑San Sebastián, Spain · Sep 2018.
A paradigm for anomalies and non‑linear responses in topological matter (poster)
LETI Innovation Days, 2nd Quantum Engineering Day. Grenoble, France · Jul 2018.
The role of the reconstruction parameter in MFP reconstruction technique (oral)
3rd Scientific Meeting of BCN‑b PhD Students in Nanoscience. Barcelona, Spain · Nov 2017.
Impact of the regularization parameter in the MFP reconstruction technique (oral)
III Severo Ochoa Scientific Workshop. ICN2, Barcelona, Spain · Jun 2017.
Dependence of the accumulation function on the regularization parameter in MFP reconstruction (poster)
Wave Phenomena and Phonon Thermal Transport. Oléron, France · Jun 2017.
Study of the impact of the regularization parameter in the phonon MFP reconstruction (poster)
E‑MRS Spring Meeting. Strasbourg, France · May 2017.
Perturbative quantization of Yang‑Mills theory with the classical double of su(N) (oral)
III Doctoral Conference of the University of Murcia. Murcia, Spain · May–Jun 2017.

Students

William Caiger (MSc)
willcaiger.com
Topological Quantum Computation with Quasicrystals. HH Wills Physics Laboratory, University of Bristol. 2024/2025.

William Caiger (left) and Miguel Ángel Sánchez (right) at the SDIQT 25 conference, where William presented his poster on the Abundance of Majorana Bound States in Quasicrystals.
Nanda Girish (MSc)
Topological Quantum Computation with Quasicrystals. HH Wills Physics Laboratory, University of Bristol. 2024/2025.

CV & Contact

Contact

Email: contact@masanchezmartinez.com
Office: Office 3.52, Department of Theoretical Physics
Postal address:
H.H. Wills Physics Laboratory
University of Bristol
Tyndall Avenue, Bristol BS8 1TL, United Kingdom

If you are interested in collaborations, research visits, or Master’s/PhD positions, feel free to email me with your CV and a short description of your research interests.

Curriculum Vitae

You can download my CV here:

Full CV (PDF)

Last updated: 02/2026.