Universität zu Köln

Germanskiy, Semyon ORCID: 0000-0002-5649-2548 (2025). Nonlinear Terahertz Spectroscopy of the 3D Dirac Material Cd₃As₂. PhD thesis, Universität zu Köln.

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Abstract

The thesis investigates the dynamics of quasi-massless electrons in the three-dimensional Dirac material Cd₃As₂ using nonlinear terahertz spectroscopy. It demonstrates that the presence of a Dirac cone in the material enables highly efficient terahertz harmonic generation, and that the generated harmonics depend on the parameters of the driving electric field. Furthermore, it explores how a thickness gradient can break overall inversion symmetry, leading to second harmonic generation. These findings advance our understanding of electron dynamics at the Dirac cone and their role in the nonlinear response of Dirac materials in the terahertz range.

Item Type:	Thesis (PhD thesis)
Translated title:	Title Language UNSPECIFIED English
Creators:	Creators Email ORCID ORCID Put Code Germanskiy, Semyon UNSPECIFIED https://orcid.org/0000-0002-5649-2548 UNSPECIFIED
Contributors:	Contribution Name Email Author UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-782416228
Date:	2025
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics II
Subjects:	Natural sciences and mathematics Physics
Uncontrolled Keywords:	Keywords Language nonlinear optics English terahertz radiation English Dirac materials English condenced matter English harmonic generation English
Date of oral exam:	18 February 2025
Referee:	Name Academic Title van Loosdrecht, Paul H. M. Prof. Dr. Ir. Pimenov, Andrei Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/78241