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The Effect of X‐Ray Irradiation on Conductivity of C and 2 C Polytype TlInS 2 Ferroelectrics
Author(s) -
Borovyi Mykola,
Gololobov Yurii P.,
Isaieva Karyna,
Isaiev Mykola
Publication year - 2021
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202000556
Subject(s) - conductivity , irradiation , materials science , atmospheric temperature range , condensed matter physics , fermi level , electrical resistivity and conductivity , phase (matter) , analytical chemistry (journal) , range (aeronautics) , electron , anomaly (physics) , x ray , chemistry , optics , physics , thermodynamics , nuclear physics , composite material , organic chemistry , chromatography , quantum mechanics
The influence of X‐ray irradiation on DC conductivity of TlInS 2 C and 2 C polytypes is studied in the temperature range of 100–300 K. The X‐ray irradiation (absorbed doses are 0.9 and 2.7 kGy) leads to an increasing conductivity of both C ‐ and 2 C ‐samples in proportion to the absorbed dose; the conductivity decreases on cooling in the temperature region of 100–300 K. An anomalous increase in conductivity is observed in C ‐polytype samples on cooling in the temperature range of the incommensurate phase (197–214 K). The X‐ray irradiation causes the “blur” of that anomaly. It is established that the mechanism of hopping conductivity with variable hopping length takes place for both polytypes in the temperature range of 125–175 K, and the densities of localized states near the Fermi level ( N F ) are determined. Under irradiation, the density N F increases from 3.7 × 10 18 eV −1 cm −3 ( C ) to 6.9 × 10 18 eV −1 cm −3 (2 C ) and exceeds the initial value more than three times at D = 2.7 kGy. Using the 1D Kroning–Penney model, the role of incommensurate periodic potential in modification of electron band structure at creation of the incommensurate phases in crystals is discussed.