The results of DFT research on the band structure of zigzag graphene nanoribbons N-ZGNR/h-BN(0001) with ferro-and antiferromagnetic ordering are presented. It is suitable as a potential base for new materials for spintronics. Equilibrium parameters of the graphene nanoribbon atomic structure and boron nitride top layer are determined as well as the equilibrium bond length between atomic layers of the 8-ZGNR nanoribbon and the substrate h-BN(0001). Change regularities of the valence band electronic structure and of the energy gap induction in series 6-ZGNR-^ 8-ZGNR-^ 6-ZGNR/h-BN(0001)^ 8-ZGNR/h-BN(0001)^ graphene/h-BN(0001) are studied. Spin state features at Fermi level, as well as the roles of the edge effect and the effect of substrate in the formation of the band gap in 6(8)-ZGNR/h-BN(0001) system are discussed. It is shown that 340 meV energy gap appears in 6(8)-ZGNR/h-BN(0001) systems. The contribution of the graphene nanoribbon edge and substrate in opening this energy gap is differentiated. Local magnetic moments on the carbon atoms in graphene nanoribbons in the suspended state and on the substrate with ferro- and antiferromagnetic ordering are estimated. It is shown that the local magnetic moments on the carbon atoms in zigzag graphene nanoribbons 8-ZGNRs with ferro- and antiferromagnetic ordering give almost identical values. The edge carbon atoms possess the largest local magnetic moments (0,28) relative to other carbon atoms.
band structure, hexagonal nitride boron, zigzag graphene nanoribbon, magnetic moments, electronic properties.
Введение. С момента открытия в 2004 году уникальные свойства графена являются объектом повышенного внимания исследователей [1, 2]. Высокая подвижность носителей заряда в графене при комнатной температуре определяет широкие перспективы его использования для создания элементов и устройств спинтроники. Энергетической щелью в зонном спектре графена можно управлять, используя различные (диэлектрические [3, 4] и металлические [5]) подложки, графе-новые наноленты [6—8] и электрическое поле [9]. Влияние, например, диэлектрической подложки А12О3(0001), оказываемое на зонный спектр графена, заключается в появлении в окрестности уровня Ферми энергетической щели шириной порядка 55 мэВ [3]. Данный разрыв связан с неэквивалентным расположением атомов алюминия подложки по отношению к атомам углерода. Графеновые наноленты интересны тем, что обладают нелинейным законом дисперсии для низкоэнергетического спектра п-электронов [7, 8]. Благодаря квантово-размерному эффекту наноленты содержат конечную запрещённую полосу Ед. Её величина зависит от ориентации границ нанолент относительно кристаллической решётки графена. Отличительной особенностью электронного спектра нанолент типа «зигзаг» {zigzag graphene nanoribbon — ZGNR) является наличие локализованных состояний на уровне Ферми, которые обусловлены атомами границ [8]. Наличие локализованных электронных состояний в графеновых нанолентах экспериментально установлено методом фотоэлектронной спектроскопии с угловым разрешением (ARPES) [10, 11].
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