Deng Haiming, Zhao Lukas, Park Kyungwha, Yan Jiaqiang, Sobczak Kamil, Lakra Ayesha, Buzi Entela, Krusin-Elbaum Lia
Department of Physics, The City College of New York - CUNY, New York, NY, 10031, United States.
Department of Physics, Virginia Tech, Blacksburg, VA, 24061, United States.
Nat Commun. 2022 Apr 28;13(1):2308. doi: 10.1038/s41467-022-29957-3.
Hydrogen, the smallest and most abundant element in nature, can be efficiently incorporated within a solid and drastically modify its electronic and structural state. In most semiconductors interstitial hydrogen binds to defects and is known to be amphoteric, namely it can act either as a donor (H) or an acceptor (H) of charge, nearly always counteracting the prevailing conductivity type. Here we demonstrate that hydrogenation resolves an outstanding challenge in chalcogenide classes of three-dimensional (3D) topological insulators and magnets - the control of intrinsic bulk conduction that denies access to quantum surface transport, imposing severe thickness limits on the bulk. With electrons donated by a reversible binding of H ions to Te(Se) chalcogens, carrier densities are reduced by over 10cm, allowing tuning the Fermi level into the bulk bandgap to enter surface/edge current channels without altering carrier mobility or the bandstructure. The hydrogen-tuned topological nanostructures are stable at room temperature and tunable disregarding bulk size, opening a breadth of device platforms for harnessing emergent topological states.
氢是自然界中最小且最丰富的元素，它能够有效地融入固体中，并极大地改变其电子和结构状态。在大多数半导体中，间隙氢与缺陷结合，已知具有两性，即它既可以作为电荷的施主（H），也可以作为受主（H），几乎总是抵消主导的导电类型。在此，我们证明氢化解决了三维（3D）拓扑绝缘体和磁体的硫族化物类别中一个突出的挑战——控制本征体传导，而本征体传导会阻碍量子表面输运，对体材料施加严格的厚度限制。通过H离子与Te（Se）硫族元素的可逆结合所提供的电子，载流子密度降低超过10cm，从而能够将费米能级调节到体能带隙中，以进入表面/边缘电流通道，而不会改变载流子迁移率或能带结构。经氢调谐的拓扑纳米结构在室温下稳定，且与体材料尺寸无关可进行调谐，为利用新兴拓扑态开辟了广泛的器件平台。
