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arXiv · 2212.03611

Fermi Level Instability as a Way to Tailor Properties of La3Te4

Muhammad Rizwan Khan·Harshan Reddy Gopidi·Mateusz Wlazło·Oleksandr I. Malyi
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Abstract

Traditionally, the formation of off-stoichiometric compounds is believed to be the growth effect rather than the intrinsic tendency of the system. However, here, using the example of La3Te4, we demonstrate that in n-type gapped metals having a large internal gap between principal band edges and the Fermi level inside of the principal conduction band, Fermi-level instability can develop, resulting in a reduction of formation energy for acceptor defects. Specifically, La vacancies in La3Te4 form spontaneously to produce the acceptor states and remove a fraction of free carriers from the principal conduction band via electron-hole recombination. Such a unique self-doping mechanism allows to stabilize a range of off-stoichiometric La3-xTe4 compounds, which have different electronic properties. Moreover, we thus show how controlling synthesis conditions can be used as a knob to reach the target functionality, including controllable metal-to-insulator transition.

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Muhammad Rizwan Khan, Harshan Reddy Gopidi, Mateusz Wlazło, Oleksandr I. Malyi. 2022-12-07. Fermi Level Instability as a Way to Tailor Properties of La3Te4. https://arxiv.org/abs/2212.03611

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