Bipolaronic Nature of the Pseudogap in Quasi-One-Dimensional (TaSe4)2I Revealed via Weak Photoexcitation

Yingchao Zhang; Chaitanya Murthy; Tika R. Kafle; Wenjing You; Xun Shi; Lujin Min; Huaiyu Hugo Wang; Na Li; Venkatraman Gopalan; Zhiqiang Mao; Kai Rossnagel; Lexian Yang; Henry Kapteyn; Rahul Nandkishore; Margaret Murnane

doi:10.1021/acs.nanolett.3c01078

Bipolaronic Nature of the Pseudogap in Quasi-One-Dimensional (TaSe₄)₂I Revealed via Weak Photoexcitation

Yingchao Zhang, Chaitanya Murthy, Tika R. Kafle, Wenjing You, Xun Shi, Lujin Min, Huaiyu Hugo Wang, Na Li, Venkatraman Gopalan, Zhiqiang Mao, Kai Rossnagel, Lexian Yang, Henry Kapteyn, Rahul Nandkishore, Margaret Murnane

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

The origin of the pseudogap in many strongly correlated materials has been a longstanding puzzle. Here, we present experimental evidence that many-body interactions among small Holstein polarons, i.e., the formation of bipolarons, are primarily responsible for the pseudogap in (TaSe₄)₂I. After weak photoexcitation of the material, we observe the appearance of both dispersive (single-particle bare band) and flat bands (single-polaron sub-bands) in the gap by using time- and angle-resolved photoemission spectroscopy. Based on Monte Carlo simulations of the Holstein model, we propose that the melting of pseudogap and emergence of new bands originate from a bipolaron to single-polaron crossover. We also observe dramatically different relaxation times for the excited in-gap states in (TaSe₄)₂I (∼600 fs) compared with another 1D material Rb_0.3MoO₃ (∼60 fs), which provides a new method for distinguishing between pseudogaps induced by polaronic or Luttinger-liquid many-body interactions.

Original language	English (US)
Pages (from-to)	8392-8398
Number of pages	7
Journal	Nano letters
Volume	23
Issue number	18
DOIs	https://doi.org/10.1021/acs.nanolett.3c01078
State	Published - Sep 27 2023

All Science Journal Classification (ASJC) codes

Bioengineering
General Chemistry
General Materials Science
Condensed Matter Physics
Mechanical Engineering

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10.1021/acs.nanolett.3c01078

Cite this

@article{25d3da6121464be1a82488df746749f7,

title = "Bipolaronic Nature of the Pseudogap in Quasi-One-Dimensional (TaSe4)2I Revealed via Weak Photoexcitation",

abstract = "The origin of the pseudogap in many strongly correlated materials has been a longstanding puzzle. Here, we present experimental evidence that many-body interactions among small Holstein polarons, i.e., the formation of bipolarons, are primarily responsible for the pseudogap in (TaSe4)2I. After weak photoexcitation of the material, we observe the appearance of both dispersive (single-particle bare band) and flat bands (single-polaron sub-bands) in the gap by using time- and angle-resolved photoemission spectroscopy. Based on Monte Carlo simulations of the Holstein model, we propose that the melting of pseudogap and emergence of new bands originate from a bipolaron to single-polaron crossover. We also observe dramatically different relaxation times for the excited in-gap states in (TaSe4)2I (∼600 fs) compared with another 1D material Rb0.3MoO3 (∼60 fs), which provides a new method for distinguishing between pseudogaps induced by polaronic or Luttinger-liquid many-body interactions.",

author = "Yingchao Zhang and Chaitanya Murthy and Kafle, {Tika R.} and Wenjing You and Xun Shi and Lujin Min and Wang, {Huaiyu Hugo} and Na Li and Venkatraman Gopalan and Zhiqiang Mao and Kai Rossnagel and Lexian Yang and Henry Kapteyn and Rahul Nandkishore and Margaret Murnane",

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doi = "10.1021/acs.nanolett.3c01078",

language = "English (US)",

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T1 - Bipolaronic Nature of the Pseudogap in Quasi-One-Dimensional (TaSe4)2I Revealed via Weak Photoexcitation

AU - Zhang, Yingchao

AU - Murthy, Chaitanya

AU - Kafle, Tika R.

AU - You, Wenjing

AU - Shi, Xun

AU - Min, Lujin

AU - Wang, Huaiyu Hugo

AU - Li, Na

AU - Gopalan, Venkatraman

AU - Mao, Zhiqiang

AU - Rossnagel, Kai

AU - Yang, Lexian

AU - Kapteyn, Henry

AU - Nandkishore, Rahul

AU - Murnane, Margaret

PY - 2023/9/27

Y1 - 2023/9/27

N2 - The origin of the pseudogap in many strongly correlated materials has been a longstanding puzzle. Here, we present experimental evidence that many-body interactions among small Holstein polarons, i.e., the formation of bipolarons, are primarily responsible for the pseudogap in (TaSe4)2I. After weak photoexcitation of the material, we observe the appearance of both dispersive (single-particle bare band) and flat bands (single-polaron sub-bands) in the gap by using time- and angle-resolved photoemission spectroscopy. Based on Monte Carlo simulations of the Holstein model, we propose that the melting of pseudogap and emergence of new bands originate from a bipolaron to single-polaron crossover. We also observe dramatically different relaxation times for the excited in-gap states in (TaSe4)2I (∼600 fs) compared with another 1D material Rb0.3MoO3 (∼60 fs), which provides a new method for distinguishing between pseudogaps induced by polaronic or Luttinger-liquid many-body interactions.

AB - The origin of the pseudogap in many strongly correlated materials has been a longstanding puzzle. Here, we present experimental evidence that many-body interactions among small Holstein polarons, i.e., the formation of bipolarons, are primarily responsible for the pseudogap in (TaSe4)2I. After weak photoexcitation of the material, we observe the appearance of both dispersive (single-particle bare band) and flat bands (single-polaron sub-bands) in the gap by using time- and angle-resolved photoemission spectroscopy. Based on Monte Carlo simulations of the Holstein model, we propose that the melting of pseudogap and emergence of new bands originate from a bipolaron to single-polaron crossover. We also observe dramatically different relaxation times for the excited in-gap states in (TaSe4)2I (∼600 fs) compared with another 1D material Rb0.3MoO3 (∼60 fs), which provides a new method for distinguishing between pseudogaps induced by polaronic or Luttinger-liquid many-body interactions.

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