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Topological band theory of driven and dissipative systems

Applicant Bzdusek Tomas
Number 185806
Funding scheme Ambizione
Research institution Condensed Matter Theory Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Condensed Matter Physics
Start/End 01.10.2019 - 30.09.2023
Approved amount 769'272.00
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Keywords (10)

band-structure nodes; non-Hermitian quantum mechanics; dissipative systems; electronic structure; semimetals; driven systems; topological invariants; magnetotransport; topological methods; condensed matter theory

Lay Summary (German)

Das übergreifende Ziel dieses Forschungsvorschlags ist die Suche nach neuartigen topologischen Phasen der Materie. Der Schwerpunkt liegt auf topologischen Phasen, die durch periodische Anregungen oder Dissipation ermöglicht sind. Frühere Forschungen legen nahe, dass diese beiden Faktoren tatsächlich neue Phasen der Materie mit einzigartigen Eigenschaften induzieren, und so die Menge zuvor entdeckter topologischer Phasen bereichern. Die Beschreibung und Klassifizierung dieser Systeme ist jedoch zur Zeit unvollständig.
Lay summary


Der vorliegende Forschungsvorschlag verfolgt zwei Ziele. Erstens, um nach einzigartigen experimentellen Fingerabdrücken der bereits bekannten topologischen Phasen zu forschen und nach geeigneten Materialien zu suchen, die diese Eigenschaften aufweisen würden. Zweitens, um zu untersuchen, ob periodische Anregungs- und Dissipationsprozesse zusätzliche topologische Phasen der Materie ermöglichen können. Um diese Ziele zu erreichen, werde ich moderne theoretische Techniken anwenden, einschließlich der elektronischen Bandtheorie, Gruppentheorie und algebraischen Topologie.

Wissenschaftlicher und gesellschaftlicher Kontext:

Zuvor entdeckte topologische Materialien (wie topologische Isolatoren, Graphen und Weyl-Halbmetalle) weisen andere Transporteigenschaften auf als Isolatoren, Metalle und Halbleiter. Dies macht sie potenziell nützlich für zukünftige Anwendungen, zum Beispiel in der Spintronik, Nanoelektronik und im Quantencomputing. Um das Potenzial topologischer Phasen der Materie voll zu verwenden, ist es wichtig, ein tieferes physikalisches Verständnis zu erlangen.



Direct link to Lay Summary Last update: 02.09.2019

Lay Summary (English)

The overarching goal of this research proposal is to search for novel topological phases of matter, with a special focus on topological phases enabled by the presence of periodic driving or dissipation. Prior research suggests that these two factors can indeed induce novel phases of matter with unique properties, thus enriching the plethora of previously discovered topological phases. However, the existing description and classification of these systems is at present largely incomplete.
Lay summary


The present research proposal has two goals. First, to search for unique experimental fingerprints of the already known topological phases, and to search for suitable materials that would exhibit these properties. Second, to study whether periodic driving and dissipative processes can enable additional topological phases of matter. To reach these goals, I will apply modern theoretical techniques, including the electronic band theory, group theory, and algebraic topology.


Scientific and societal context:

Previously discovered topological materials (such as topological insulators, graphene, and Weyl semimetals), exhibit transport properties distinct from insulators, metals and semiconductors. This makes them potentially useful for future applications, for example in spintronics, nanoelectronic, and quantum computing. To fully exploit the potential of topological phases of matter, it is important to obtain their deeper physical understanding.

Direct link to Lay Summary Last update: 02.09.2019

Responsible applicant and co-applicants



The presented research proposal aims to study topological band structures. This includes characterization of topological invariants in the presence of crystalline symmetries, investigating the transport signatures of topologically non-trivial bands, and considering their experimental realizations. Special focus would be paid to periodically driven “Floquet” and dissipative “non-Hermitian” systems that became experimentally achievable over the past decade.The research proposal specifically focuses on (but is not limited to) the following four projects: (1) Magnetotransport in topological metals and semimetals.(2) Classification and properties of band-structure nodes (3) Topological band theory of periodically driven systems.(4) Metals and semimetals in non-Hermitian systems.These theoretical projects can be developed in parallel with related computational and experimental efforts carried at the Paul Scherrer Institute, and with research teams in Zürich and Lausanne. Doctoral student would be assigned a project focusing on the transport properties of topological semimetals, and on experimental signatures of band singularities in Floquet systems. A successful completion of these projects would significantly enhance our understanding of the mechanisms behind the occurrence of topological band structures, identify their experimentally measurable signatures, and facilitate the search for these novel phases of matter in existing materials as well as in artificially engineered systems.