Computational Nanoelectronics and Emerging Devices Group
CNEG’s research is focused on the theoretical and computational investigation of device science and engineering based on nanoelectronics, spintronics, and advanced materials, with an emphasis on low-power consumption applications and nonvolatile electronic system. The research topics are engaged in a dynamic and multidisciplinary research program requiring (1) fundamental understanding of materials to discover original and unique properties and their affects on carrier, spin and heat transport, and (2) a creative engineering approach to innovate and realize novel devices. The studied devices widely include the electronic, thermoelectric, optoelectronic, electron-optics, magnetic, and spintronic devices. Many of our theoretical predictions have been confirmed by experimental measurements.
Latest news
The paper "Real space characterization of nonlinear hall effect in confined directions" by Sheng Luo, Chuang-Han Hsu, Guoqing Chang, Arun Bansil, Hsin Lin, Gengchiau Liang* is published in Nature Publishing Group UK.
The nonlinear Hall effect (NLHE) is a phenomenon which could produce a transverse Hall voltage in a time-reversal-invariant material. Here, we report the real space characterizations of NLHE evaluated through quantum transport in TaIrTe4 nanoribbon without the explicit Berry curvature dipole (BCD) information. We first characterize the NLHE in both transverse confined directions in global-level measurement. The impact of quantum confinement in NLHE is evaluated by adjusting the width of nanoribbons. Then, the probing area is trimmed to the atomic scale to evaluate the local texture, where we discover its patterns differ among the probed neighboring atomic groups. The analysis of charge distribution reveals the connections between NLHE’s local patterns and its non-centrosymmetric nature, rendering nearly an order of Hall voltage enhancement through probe positioning. Our work paves the way to expand the range of NLHE study and unveil its physics in more versatile material systems.
The paper "Tunable and inhomogeneous current-induced THz-oscillation dynamics in the ferrimagnetic spin-chain" by Baofang Cai, Xue Zhang, Zhifeng Zhu, Gengchiau Liang* is published in Communications Physics.
Ferrimagnets perform versatile properties, attributed to their antiferromagnetic sublattice coupling and finite net magnetization. Despite extensive research, the inhomogeneous dynamics in ferrimagnets, including domain walls and magnons, remain not fully understood. Therefore, we adopted a multi-spin model by considering the effect of the spin torques and explored the localized phase-dependent and inhomogeneous THz-oscillation dynamics in a ferrimagnetic spin-chain. Our results demonstrate that the exchange oscillation mode, induced by spin transfer torque, exhibits three typical phases, and the oscillation frequency is dominated by a joint effective field derived in the spin-chain.Wealsofoundthatthelocalizedspinconfigurationscanbeusedtotunethebandwidthand sensitivity of the frequency response. Furthermore, we propose an anti-parallel exchange length to reveal the inhomogeneity in the ferrimagnetic spin-chain, which could serve as a valuable tool for characterizing thespindynamicsofthesesystems.Ourfindingsofferunderstandingsbeyonduniform spin-dynamics in ferrimagnets.