Electrical transport properties driven by unique bonding configuration in gamma-GeSe

• Published in: arXiv.org 2023-04
• Main Authors: Jang, Jeongsu, Kim, Joonho, Sung, Dongchul, Kim, Jong Hyuk, Jung, Joong-Eon, Lee, Sol, Park, Jinsub, Lee, Chaewoon, Bae, Heesun, Im, Seongil, Park, Kibog, Choi, Young Jai, Hong, Suklyun, Kim, Kwanpyo
• Format: Article
• Language: English
• Subjects: Bonding; Configurations; Doping; Electrical properties; Electrical resistivity; Ferroelectricity; First principles; Magnetoresistance; Magnetoresistivity; Physical properties; Room temperature; Seebeck effect; Spin-orbit interactions; Thermoelectricity; Transport properties
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2304.06954

Group-IV monochalcogenides have recently shown great potential for their thermoelectric, ferroelectric, and other intriguing properties. The electrical properties of group-IV monochalcogenides exhibit a strong dependence on the chalcogen type. For example, GeTe exhibits high doping concentration, whereas S/Se-based chalcogenides are semiconductors with sizable bandgaps. Here, we investigate the electrical and thermoelectric properties of gamma-GeSe, a recently identified polymorph of GeSe. gamma-GeSe exhibits high electrical conductivity (~106 S/m) and a relatively low Seebeck coefficient (9.4 uV/K at room temperature) owing to its high p-doping level (5x1021 cm-3), which is in stark contrast to other known GeSe polymorphs. Elemental analysis and first-principles calculations confirm that the abundant formation of Ge vacancies leads to the high p-doping concentration. The magnetoresistance measurements also reveal weak-antilocalization because of spin-orbit coupling in the crystal. Our results demonstrate that gamma-GeSe is a unique polymorph in which the modified local bonding configuration leads to substantially different physical properties.