Demonstrating the quasilocalized nature of the Sn impurity states in Bi2Te2Se

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F25%3A00635850" target="_blank" >RIV/68378271:_____/25:00635850 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1103/PhysRevB.111.205202" target="_blank" >https://doi.org/10.1103/PhysRevB.111.205202</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevB.111.205202" target="_blank" >10.1103/PhysRevB.111.205202</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Demonstrating the quasilocalized nature of the Sn impurity states in Bi2Te2Se

Popis výsledku v původním jazyce

Binary M2X3 compounds (M = Sb, Bi and X = S, Se, Te) and their solid solutions are among the most efficient materials for thermoelectric applications near room temperature. In the canonical compound Bi2Te3, Sn has been shown to induce a resonant level (RL) similar to 15 meV below the valence band edge, leading to enhanced thermopower values with respect to those achieved with rigidlike impurities. However, the question of whether Sn is still a resonant impurity in ternary alloys and notably, in the topological insulator Bi2Te2Se, remains unsettled. Here, we demonstrate experimentally that Sn loses its resonant character in Bi2Te2Se. Alloying with Pb in Bi1.99-ySn0.01PbyTe2Se rigidly shifts the chemical potential towards the valence bands and reveals a metal-insulator transition at low temperatures, which can be well described by an Sn impurity level that dominates the electrical conduction up to y = 0.020. Further increasing y to 0.025 and 0.030 progressively restores a conventional valence band conduction. The presence of the Sn impurity level that forms a density-of-states peak disconnected from the valence band manifold is supported by electronic band structure calculations. Due to the quasilocalized nature of this impurity level, the addition of Sn does not enhance the thermopower values compared to those measured in Sn-free samples, resulting in comparable thermoelectric performance, with a peak ZT value of 0.70 achieved at 425 K for y = 0.01.

Název v anglickém jazyce

Demonstrating the quasilocalized nature of the Sn impurity states in Bi2Te2Se

Popis výsledku anglicky

Binary M2X3 compounds (M = Sb, Bi and X = S, Se, Te) and their solid solutions are among the most efficient materials for thermoelectric applications near room temperature. In the canonical compound Bi2Te3, Sn has been shown to induce a resonant level (RL) similar to 15 meV below the valence band edge, leading to enhanced thermopower values with respect to those achieved with rigidlike impurities. However, the question of whether Sn is still a resonant impurity in ternary alloys and notably, in the topological insulator Bi2Te2Se, remains unsettled. Here, we demonstrate experimentally that Sn loses its resonant character in Bi2Te2Se. Alloying with Pb in Bi1.99-ySn0.01PbyTe2Se rigidly shifts the chemical potential towards the valence bands and reveals a metal-insulator transition at low temperatures, which can be well described by an Sn impurity level that dominates the electrical conduction up to y = 0.020. Further increasing y to 0.025 and 0.030 progressively restores a conventional valence band conduction. The presence of the Sn impurity level that forms a density-of-states peak disconnected from the valence band manifold is supported by electronic band structure calculations. Due to the quasilocalized nature of this impurity level, the addition of Sn does not enhance the thermopower values compared to those measured in Sn-free samples, resulting in comparable thermoelectric performance, with a peak ZT value of 0.70 achieved at 425 K for y = 0.01.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

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

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

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

2469-9969

Svazek periodika

111

Číslo periodika v rámci svazku

20

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

16

Strana od-do

205202

Kód UT WoS článku

001494685200005

EID výsledku v databázi Scopus

2-s2.0-105005151273