Condensed Matter Seminar: Holographic Maps of Quasiparticle Interference

Emanuele Dalla Torre, Bar-Ilan University

23 January 2017, 11:00 
Kaplun Building, Flekser Hall 118 
Condensed Matter Seminar

Abstract:

The analysis of Fourier-transformed scanning-tunneling-microscopy (STM) images with subatomic resolution is a common tool for studying properties of quasiparticle excitations in strongly correlated materials. While Fourier amplitudes are generally complex valued, earlier analysis mostly considered only their absolute values. Their complex phases were deemed random, and thus irrelevant, due to the unknown positions of impurities in the sample. Here we show how to factor out these random phases by analysing overlaps between Fourier amplitudes that differ by reciprocal lattice vectors. The resulting holographic maps provide important and previously-unknown information about the electronic structures of materials. When applied to superconducting cuprates, our method solves a long-standing puzzle of the dichotomy between equivalent wavevectors. We show  that $d$-wave Wannier functions of the conduction band provide a natural explanation for experimental results that were interpreted as evidence for competing unconventional charge modulations. Our work opens a new pathway to identify the nature of electronic states in STM measurements. 

 

REFERENCE: Dalla Torre, He, Demler, Nature Physics 12, 1052-1056 (2016)

 

Event Organizer: Prof. Eli Eisenberg

 

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