Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator

Abstract Excitonic insulator is a coherent electronic phase that results from the formation of a macroscopic population of bound particle-hole pairs—excitons. With only a few candidate materials known, the collective excitonic behavior is challenging to observe, being obscured by crystalline lattice...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	P. A. Volkov, Mai Ye, H. Lohani, I. Feldman, A. Kanigel, G. Blumberg
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Materials of engineering and construction. Mechanics of materials TA401-492 Atomic physics. Constitution and properties of matter QC170-197
Acceso en línea:	https://doaj.org/article/b42dbaba85d345a0806b789274e34039
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:b42dbaba85d345a0806b789274e34039
record_format	dspace
spelling	oai:doaj.org-article:b42dbaba85d345a0806b789274e340392021-12-02T15:49:42ZCritical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator10.1038/s41535-021-00351-42397-4648https://doaj.org/article/b42dbaba85d345a0806b789274e340392021-05-01T00:00:00Zhttps://doi.org/10.1038/s41535-021-00351-4https://doaj.org/toc/2397-4648Abstract Excitonic insulator is a coherent electronic phase that results from the formation of a macroscopic population of bound particle-hole pairs—excitons. With only a few candidate materials known, the collective excitonic behavior is challenging to observe, being obscured by crystalline lattice effects. Here we use polarization-resolved Raman spectroscopy to reveal the quadrupolar excitonic mode in the candidate zero-gap semiconductor Ta2NiSe5 disentangling it from the lattice phonons. The excitonic mode pronouncedly softens close to the phase transition, showing its electronic character, while its coupling to noncritical lattice modes is shown to enhance the transition temperature. On cooling, we observe the gradual emergence of coherent superpositions of band states at the correlated insulator gap edge, with strong departures from mean-field theory predictions. Our results demonstrate the realization of a strongly correlated excitonic state in an equilibrium bulk material.P. A. VolkovMai YeH. LohaniI. FeldmanA. KanigelG. BlumbergNature PortfolioarticleMaterials of engineering and construction. Mechanics of materialsTA401-492Atomic physics. Constitution and properties of matterQC170-197ENnpj Quantum Materials, Vol 6, Iss 1, Pp 1-9 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Materials of engineering and construction. Mechanics of materials TA401-492 Atomic physics. Constitution and properties of matter QC170-197
spellingShingle	Materials of engineering and construction. Mechanics of materials TA401-492 Atomic physics. Constitution and properties of matter QC170-197 P. A. Volkov Mai Ye H. Lohani I. Feldman A. Kanigel G. Blumberg Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator
description	Abstract Excitonic insulator is a coherent electronic phase that results from the formation of a macroscopic population of bound particle-hole pairs—excitons. With only a few candidate materials known, the collective excitonic behavior is challenging to observe, being obscured by crystalline lattice effects. Here we use polarization-resolved Raman spectroscopy to reveal the quadrupolar excitonic mode in the candidate zero-gap semiconductor Ta2NiSe5 disentangling it from the lattice phonons. The excitonic mode pronouncedly softens close to the phase transition, showing its electronic character, while its coupling to noncritical lattice modes is shown to enhance the transition temperature. On cooling, we observe the gradual emergence of coherent superpositions of band states at the correlated insulator gap edge, with strong departures from mean-field theory predictions. Our results demonstrate the realization of a strongly correlated excitonic state in an equilibrium bulk material.
format	article
author	P. A. Volkov Mai Ye H. Lohani I. Feldman A. Kanigel G. Blumberg
author_facet	P. A. Volkov Mai Ye H. Lohani I. Feldman A. Kanigel G. Blumberg
author_sort	P. A. Volkov
title	Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator
title_short	Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator
title_full	Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator
title_fullStr	Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator
title_full_unstemmed	Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator
title_sort	critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/b42dbaba85d345a0806b789274e34039
work_keys_str_mv	AT pavolkov criticalchargefluctuationsandemergentcoherenceinastronglycorrelatedexcitonicinsulator AT maiye criticalchargefluctuationsandemergentcoherenceinastronglycorrelatedexcitonicinsulator AT hlohani criticalchargefluctuationsandemergentcoherenceinastronglycorrelatedexcitonicinsulator AT ifeldman criticalchargefluctuationsandemergentcoherenceinastronglycorrelatedexcitonicinsulator AT akanigel criticalchargefluctuationsandemergentcoherenceinastronglycorrelatedexcitonicinsulator AT gblumberg criticalchargefluctuationsandemergentcoherenceinastronglycorrelatedexcitonicinsulator
_version_	1718385713215438848

Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator

Ejemplares similares