Zhou Jiawei, Zhu Hangtian, Song Qichen, Ding Zhiwei, Mao Jun, Ren Zhifeng, Chen Gang
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Department of Physics and Texas Center for Superconductivity at the University of Houston (TcSUH), University of Houston, Houston, TX, 77204, USA.
Nat Commun. 2022 May 6;13(1):2482. doi: 10.1038/s41467-022-29958-2.
Doping is central for solid-state devices from transistors to thermoelectric energy converters. The interaction between electrons and dopants plays a pivotal role in carrier transport. Conventional theory suggests that the Coulomb field of the ionized dopants limits the charge mobility at high carrier densities, and that either the atomic details of the dopants are unimportant or the mobility can only be further degraded, while experimental results often show that dopant choice affects mobility. In practice, the selection of dopants is still mostly a trial-and-error process. Here we demonstrate, via first-principles simulation and comparison with experiments, that a large short-range perturbation created by selected dopants can in fact counteract the long-range Coulomb field, leading to electron transport that is nearly immune to the presence of dopants. Such "cloaking" of dopants leads to enhanced mobilities at high carrier concentrations close to the intrinsic electron-phonon scattering limit. We show that the ionic radius can be used to guide dopant selection in order to achieve such an electron-cloaking effect. Our finding provides guidance to the selection of dopants for solid-state conductors to achieve high mobility for electronic, photonic, and energy conversion applications.
掺杂对于从晶体管到热电能量转换器的固态器件至关重要。电子与掺杂剂之间的相互作用在载流子输运中起着关键作用。传统理论认为，电离掺杂剂的库仑场在高载流子密度下会限制电荷迁移率，并且要么掺杂剂的原子细节不重要，要么迁移率只会进一步降低，而实验结果常常表明掺杂剂的选择会影响迁移率。在实际应用中，掺杂剂的选择仍然大多是一个反复试验的过程。在此，我们通过第一性原理模拟并与实验进行比较，证明所选掺杂剂产生的大的短程微扰实际上可以抵消长程库仑场，从而导致电子输运几乎不受掺杂剂存在的影响。这种掺杂剂的“隐身”效应在接近本征电子 - 声子散射极限的高载流子浓度下会提高迁移率。我们表明离子半径可用于指导掺杂剂的选择，以实现这种电子隐身效果。我们的发现为固态导体掺杂剂的选择提供了指导，以便在电子、光子和能量转换应用中实现高迁移率。
