Hidden Local Symmetry Breaking in Silver Diamondoid Compounds is Root Cause of Ultralow Thermal Conductivity

Hongyao Xie; Emil S. Bozin; Zhi Li; Milinda Abeykoon; Soham Banerjee; James P. Male; G. Jeffrey Snyder; Christopher Wolverton; Simon J.L. Billinge; Mercouri G. Kanatzidis

doi:10.1002/adma.202202255

Hidden Local Symmetry Breaking in Silver Diamondoid Compounds is Root Cause of Ultralow Thermal Conductivity

Hongyao Xie, Emil S. Bozin, Zhi Li, Milinda Abeykoon, Soham Banerjee, James P. Male, G. Jeffrey Snyder, Christopher Wolverton, Simon J.L. Billinge, Mercouri G. Kanatzidis^*

^*Corresponding author for this work

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

37 Scopus citations

Abstract

Typically, conventional structure transitions occur from a low symmetry state to a higher symmetry state upon warming. In this work, an unexpected local symmetry breaking in the tetragonal diamondoid compound AgGaTe₂ is reported, which, upon warming, evolves continuously from an undistorted ground state to a locally distorted state while retaining average crystallographic symmetry. This is a rare phenomenon previously referred to as emphanisis. This distorted state, caused by the weak sd³ orbital hybridization of tetrahedral Ag atoms, causes their displacement off the tetrahedron center and promotes a global distortion of the crystal structure resulting in strong acoustic–optical phonon scattering and an ultralow lattice thermal conductivity of 0.26 W m⁻¹ K⁻¹ at 850 K in AgGaTe₂. The findings explain the underlying reason for the unexpectedly low thermal conductivities of silver-based compounds compared to copper-based analogs and provide a guideline to suppressing heat transport in diamondoid and other materials.

Original language	English (US)
Article number	2202255
Journal	Advanced Materials
Volume	34
Issue number	24
DOIs	https://doi.org/10.1002/adma.202202255
State	Published - Jun 16 2022

Funding

This work was primarily supported by a grant from the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences under Award number DE‐SC0014520. Work at Brookhaven National Laboratory was supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (DOE‐BES) under Contract no. DE‐SC0012704. The X‐ray PDF measurements were conducted in part on beamline 28‐ID‐1 of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract no. DE‐SC0012704. The authors also acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Parts of this research were carried out PETRA III, beamline P21.1.

Keywords

chalcopyrites
emphanisis
thermal conductivity
thermoelectrics

ASJC Scopus subject areas

Mechanics of Materials
Mechanical Engineering
General Materials Science

Access to Document

10.1002/adma.202202255

Cite this

@article{f2845bece86345d584e0220e0f36226d,

title = "Hidden Local Symmetry Breaking in Silver Diamondoid Compounds is Root Cause of Ultralow Thermal Conductivity",

abstract = "Typically, conventional structure transitions occur from a low symmetry state to a higher symmetry state upon warming. In this work, an unexpected local symmetry breaking in the tetragonal diamondoid compound AgGaTe2 is reported, which, upon warming, evolves continuously from an undistorted ground state to a locally distorted state while retaining average crystallographic symmetry. This is a rare phenomenon previously referred to as emphanisis. This distorted state, caused by the weak sd3 orbital hybridization of tetrahedral Ag atoms, causes their displacement off the tetrahedron center and promotes a global distortion of the crystal structure resulting in strong acoustic–optical phonon scattering and an ultralow lattice thermal conductivity of 0.26 W m−1 K−1 at 850 K in AgGaTe2. The findings explain the underlying reason for the unexpectedly low thermal conductivities of silver-based compounds compared to copper-based analogs and provide a guideline to suppressing heat transport in diamondoid and other materials.",

keywords = "chalcopyrites, emphanisis, thermal conductivity, thermoelectrics",

author = "Hongyao Xie and Bozin, {Emil S.} and Zhi Li and Milinda Abeykoon and Soham Banerjee and Male, {James P.} and Snyder, {G. Jeffrey} and Christopher Wolverton and Billinge, {Simon J.L.} and Kanatzidis, {Mercouri G.}",

note = "Publisher Copyright: {\textcopyright} 2022 Wiley-VCH GmbH.",

year = "2022",

month = jun,

day = "16",

doi = "10.1002/adma.202202255",

language = "English (US)",

volume = "34",

journal = "Advanced Materials",

issn = "0935-9648",

publisher = "Wiley-Blackwell",

number = "24",

}

TY - JOUR

T1 - Hidden Local Symmetry Breaking in Silver Diamondoid Compounds is Root Cause of Ultralow Thermal Conductivity

AU - Xie, Hongyao

AU - Bozin, Emil S.

AU - Li, Zhi

AU - Abeykoon, Milinda

AU - Banerjee, Soham

AU - Male, James P.

AU - Snyder, G. Jeffrey

AU - Wolverton, Christopher

AU - Billinge, Simon J.L.

AU - Kanatzidis, Mercouri G.

PY - 2022/6/16

Y1 - 2022/6/16

N2 - Typically, conventional structure transitions occur from a low symmetry state to a higher symmetry state upon warming. In this work, an unexpected local symmetry breaking in the tetragonal diamondoid compound AgGaTe2 is reported, which, upon warming, evolves continuously from an undistorted ground state to a locally distorted state while retaining average crystallographic symmetry. This is a rare phenomenon previously referred to as emphanisis. This distorted state, caused by the weak sd3 orbital hybridization of tetrahedral Ag atoms, causes their displacement off the tetrahedron center and promotes a global distortion of the crystal structure resulting in strong acoustic–optical phonon scattering and an ultralow lattice thermal conductivity of 0.26 W m−1 K−1 at 850 K in AgGaTe2. The findings explain the underlying reason for the unexpectedly low thermal conductivities of silver-based compounds compared to copper-based analogs and provide a guideline to suppressing heat transport in diamondoid and other materials.

AB - Typically, conventional structure transitions occur from a low symmetry state to a higher symmetry state upon warming. In this work, an unexpected local symmetry breaking in the tetragonal diamondoid compound AgGaTe2 is reported, which, upon warming, evolves continuously from an undistorted ground state to a locally distorted state while retaining average crystallographic symmetry. This is a rare phenomenon previously referred to as emphanisis. This distorted state, caused by the weak sd3 orbital hybridization of tetrahedral Ag atoms, causes their displacement off the tetrahedron center and promotes a global distortion of the crystal structure resulting in strong acoustic–optical phonon scattering and an ultralow lattice thermal conductivity of 0.26 W m−1 K−1 at 850 K in AgGaTe2. The findings explain the underlying reason for the unexpectedly low thermal conductivities of silver-based compounds compared to copper-based analogs and provide a guideline to suppressing heat transport in diamondoid and other materials.

KW - chalcopyrites

KW - emphanisis

KW - thermal conductivity

KW - thermoelectrics

UR - http://www.scopus.com/inward/record.url?scp=85129491972&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85129491972&partnerID=8YFLogxK

U2 - 10.1002/adma.202202255

DO - 10.1002/adma.202202255

M3 - Article

C2 - 35412675

AN - SCOPUS:85129491972

SN - 0935-9648

VL - 34

JO - Advanced Materials

JF - Advanced Materials

IS - 24

M1 - 2202255

ER -

Hidden Local Symmetry Breaking in Silver Diamondoid Compounds is Root Cause of Ultralow Thermal Conductivity

Abstract

Funding

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this