Vacancies in SnSe single crystals in a near-equilibrium state

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F19%3A39915147" target="_blank" >RIV/00216275:25310/19:39915147 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68378271:_____/19:00519172 RIV/00216208:11320/19:10398925 RIV/00216224:14740/19:00109219

Výsledek na webu

<a href="http://10.1103/PhysRevB.99.035306" target="_blank" >http://10.1103/PhysRevB.99.035306</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevB.99.035306" target="_blank" >10.1103/PhysRevB.99.035306</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Vacancies in SnSe single crystals in a near-equilibrium state

Popis výsledku v původním jazyce

The development of intrinsic vacancies in SnSe single crystals was investigated as a function of annealing temperature by means of positron annihilation spectroscopy accompanied by transport measurements. It has been demonstrated that two types of vacancies are present in single-crystalline SnSe. While Sn vacancies dominate in the low-temperature region, Se vacancies and vacancy clusters govern the high-temperature region. These findings are supported by theoretical calculations enabling direct detection and quantification of the most favorable type of vacancies. The experiments show that Sn vacancies couple with one or more Se vacancies with increasing temperature to form vacancy clusters. Interestingly, the clusters survive the α→β transition at ≈800 K and even grow in size with temperature. The concentration of both Se vacancies and vacancy clusters increases with temperature, similar to thermoelectric performance. This indicates that the extraordinary thermoelectric properties of SnSe are related to point defects. We suggest that either these defects vary the band structure in favor of high thermoelectric performance or introduce an energy-dependent scattering of free carriers realizing, in fact, energy filtering of the free carriers. Cluster defects account for the glasslike thermal conductivity of SnSe at elevated temperatures.

Název v anglickém jazyce

Vacancies in SnSe single crystals in a near-equilibrium state

Popis výsledku anglicky

The development of intrinsic vacancies in SnSe single crystals was investigated as a function of annealing temperature by means of positron annihilation spectroscopy accompanied by transport measurements. It has been demonstrated that two types of vacancies are present in single-crystalline SnSe. While Sn vacancies dominate in the low-temperature region, Se vacancies and vacancy clusters govern the high-temperature region. These findings are supported by theoretical calculations enabling direct detection and quantification of the most favorable type of vacancies. The experiments show that Sn vacancies couple with one or more Se vacancies with increasing temperature to form vacancy clusters. Interestingly, the clusters survive the α→β transition at ≈800 K and even grow in size with temperature. The concentration of both Se vacancies and vacancy clusters increases with temperature, similar to thermoelectric performance. This indicates that the extraordinary thermoelectric properties of SnSe are related to point defects. We suggest that either these defects vary the band structure in favor of high thermoelectric performance or introduce an energy-dependent scattering of free carriers realizing, in fact, energy filtering of the free carriers. Cluster defects account for the glasslike thermal conductivity of SnSe at elevated temperatures.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20501 - Materials engineering

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review B

ISSN

2469-9950

e-ISSN

—

Svazek periodika

99

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

12

Strana od-do

"035306-1"-"035306-12"

Kód UT WoS článku

000456031900004

EID výsledku v databázi Scopus

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