641 citations · 3.5k across the 27 of their papers we have counts for
27 papers
Exciton-polaron Umklapp scattering in Wigner crystals
Erfu Liu, Matthew Wilson, Jenny Hu +9
Strong Coulomb interactions in two-dimensional (2D) semiconductors give rise to tightly bound excitons, exciton polarons, and correlated electronic phases such as Wigner crystals (…
Brightening interlayer excitons by electric-field-driven hole transfer in bilayer WSe2
Tianyi Ouyang, Erfu Liu, Soonyoung Cha +8
We observe the interlayer A1s^I, A2s^I, and B1s^I excitons in bilayer WSe2 under applied electric fields using reflectance contrast spectroscopy. Remarkably, these interlayer excit…
A Non-Hermitian Moiré Valley Filter
Kai Shao, Hao Geng, Erfu Liu +3
A valley filter capable of generating a valley-polarized current is a crucial element in valleytronics, yet its implementation remains challenging. Here, we propose a valley filter…
Electric-field-tunable intervalley excitons and phonon replicas in bilayer WSe
Mashael M. Altaiary, Erfu Liu, Ching-Tarng Liang +7
We report the direct observation of intervalley exciton between the Q conduction valley and valence valley in bilayer WSe by photoluminescence. The Q exciton lies at ~18…
Excitonic and valleytronic signatures of correlated states at fractional fillings of a moiré superlattice
Erfu Liu, Takashi Taniguchi, Kenji Watanabe +3
Moiré superlattices are excellent platforms to realize strongly correlated quantum phenomena, such as Mott insulation and superconductivity. In particular, recent research has reve…
Gate-tunable exciton-polaron Rydberg series with strong roton effect
Erfu Liu, Jeremiah van Baren, Zhengguang Lu +5
The electronic exciton polaron is a hypothetical many-body quasiparticle formed by an exciton dressed with a polarized electron-hole cloud in the Fermi sea (FS). It is predicted to…
Multipath optical recombination of intervalley dark excitons and trions in monolayer WSe
Erfu Liu, Jeremiah van Baren, Ching-Tarng Liang +5
Excitons and trions (or exciton-polarons) in transition metal dichalcogenides (TMDs) are known to decay predominantly through intravalley transitions. Electron-hole recombination a…
Landau-quantized excitonic absorption and luminescence in a monolayer valley semiconductor
Erfu Liu, Jeremiah van Baren, Takashi Taniguchi +3
We investigate Landau-quantized excitonic absorption and luminescence of monolayer WSe under magnetic field. We observe gate-dependent quantum oscillations in the bright excito…
Valley-selective chiral phonon replicas of dark excitons and trions in monolayer WSe2
Erfu Liu, Jeremiah van Baren, Takashi Taniguchi +3
We observe a set of three replica luminescent peaks at ~21.4 meV below the dark exciton, negative and positive dark trions (or exciton-polarons) in monolayer WSe2. The replica reds…
Magneto-photoluminescence of exciton Rydberg states in monolayer WSe
Erfu Liu, Jeremiah van Baren, Takashi Taniguchi +3
Monolayer WSe hosts a series of exciton Rydberg states denoted by the principal quantum number n = 1, 2, 3, etc. While most research focuses on their absorption properties, the…
Gate tunable dark trions in monolayer WSe
Erfu Liu, Jeremiah van Baren, Zhengguang Lu +5
We report the observation and gate manipulation of intrinsic dark trions in monolayer WSe. By using ultraclean WSe devices encapsulated by boron nitride, we directly resolv…
Experimental identification of critical condition for drastically enhancing thermoelectric power factor of two-dimensional layered materials
Junwen Zeng, Xin He, Shi-Jun Liang +16
Nano-structuring is an extremely promising path to high performance thermoelectrics. Favorable improvements in thermal conductivity are attainable in many material systems, and the…
Proximity-Induced Superconductivity with Subgap Anomaly in Type II Weyl Semi-Metal WTe2
Qiao Li, Chaocheng He, Yaojia Wang +16
Due to the non-trivial topological band structure in type-II Weyl semimetal Tungsten ditelluride (WTe2), unconventional properties may emerge in its superconducting phase. While re…
Negative Photoconductance in van der Waals Heterostructures-Based Floating Gate Phototransistor
Yu Wang, Erfu Liu, Anyuan Gao +9
Van der Waals (vdW) heterostructures made of two-dimensional materials have been demonstrated to be versatile architectures for optoelectronic applications due to strong light-matt…
Gate-Induced Interfacial Superconductivity in 1T-SnSe2
Junwen Zeng, Erfu Liu, Yajun Fu +16
Layered metal chalcogenide materials provide a versatile platform to investigate emergent phenomena and two-dimensional (2D) superconductivity at/near the atomically thin limit. In…
Analog Circuit Applications based on Ambipolar Graphene/MoTe2 Vertical Transistors
Chen Pan, Yajun Fu, Jiaxin Wang +12
The current integrated circuit (IC) technology based on conventional MOS-FET (metal-oxide-semiconductor field-effect transistor) is approaching the limit of miniaturization with in…
Gated Tuned Superconductivity and Phonon Softening in Mono- and Bilayer MoS
Yajun Fu, Erfu Liu, Hongtao Yuan +16
Superconductors at the atomic two-dimensional (2D) limit are the focus of an enduring fascination in the condensed matter community. This is because, with reduced dimensions, the e…
Cleavage Tendency of Anisotropic Two Dimensional Materials: ReX2 (X=S, Se) and WTe2
Haifeng Wang, Erfu Liu, Yu Wang +4
With unique distorted 1T structure and the associated in-plane anisotropic properties, mono- and few-layer ReX2 (X=S, Se) have recently attracted particular interest. Based on expe…
Intrinsic p-type W-based transition metal dichalcogenide by substitutional Ta-doping
Yajun Fu, Mingsheng Long, Anyuan Gao +10
Two-dimensional (2D) transition metal dichalcogenides (TMDs) have recently emerged as promising candidates for future electronics and optoelectronics. While most of TMDs are intrin…
Room-temperature high detectivity mid-infrared photodetectors based on black arsenic phosphorus
Mingsheng Long, Anyuan Gao, Peng Wang +12
The mid-infrared (MIR) spectral range, pertaining to important applications such as molecular 'fingerprint' imaging, remote sensing, free space telecommunication and optical radar,…
Gate-Tunable Negative Longitudinal Magnetoresistance in the Predicted Type-II Weyl Semimetal WTe2
Yaojia Wang, Erfu Liu, Huimei Liu +13
The progress in exploiting new electronic materials and devices has been a major driving force in solid-state physics. As a new state of matter, a Weyl semimetal (WSM), particularl…
Broadband Photovoltaic Detectors based on an Atomically Thin Heterostructure
Mingsheng Long, Erfu Liu, Peng Wang +19
Van der Waals junctions of two-dimensional materials with an atomically sharp interface open up unprecedented opportunities to design and study functional heterostructures. Semicon…
High responsivity phototransistors based on few-layer ReS2 for weak signal detection
Erfu Liu, Mingsheng Long, Junwen Zeng +18
Two-dimensional transition metal dichalcogenides are emerging with tremendous potential in many optoelectronic applications due to their strong light-matter interactions. To fully…
The positive piezoconductive effect in graphene
Kang Xu, Ke Wang, Wei Zhao +17
As the thinnest conductive and elastic material, graphene is expected to play a crucial role in post-Moore era. Besides applications on electronic devices, graphene has shown great…