Publications (32)
Persistent photogenerated state attained by femtosecond laser irradiation of thin -MoTe
Meixin Cheng, Shazhou Zhong, Nicolás Rivas +9
Laser excitation has emerged as a means to expose hidden states of matter and promote phase transitions on demand. Such laser induced transformations are often rendered possible ow…
Atomic and electronic reconstruction at van der Waals interface in twisted bilayer graphene
Hyobin Yoo, Rebecca Engelke, Stephen Carr +14
Control of the interlayer twist angle in two-dimensional (2D) van der Waals (vdW) heterostructures enables one to engineer a quasiperiodic moiré superlattice of tunable length sca…
Origin of magnetoresistance suppression in thin -MoTe
Shazhou Zhong, Archana Tiwari, George Nichols +4
We use both classical magnetotransport and quantum oscillation measurements to study the thickness evolution of the extremely large magnetoresistance (XMR) material and type-II Wey…
Generation and detection of coherent longitudinal acoustic waves in ultrathin 1T'-MoTe2
Nicolas Rivas, Shazhou Zhong, Tina Dekker +9
Layered transition metal dichalcogenides have attracted substantial attention owing to their versatile functionalities and compatibility with current nanofabrication technologies.…
Observation and Control of the Magnetic Photogalvanic Effect from Strongly Bound Excitons
Xianfan Nie, Tarun Patel, Hyunggeun Lee +11
Photogalvanic effects arising from the quantum geometry of noncentrosymmetric materials are promising for next-generation light-harvesting devices that do not require a built-in el…
Raman fingerprint of two terahertz spin wave branches in a two-dimensional honeycomb Ising ferromagnet
Wencan Jin, Hyun Ho Kim, Zhipeng Ye +13
Two-dimensional (2D) magnetism has been long sought-after and only very recently realized in atomic crystals of magnetic van der Waals materials. So far, a comprehensive understand…
Macroscopic Tunneling Probe of Moiré Spin Textures in Twisted CrI
Bowen Yang, Tarun Patel, Meixin Cheng +10
Various noncollinear spin textures and magnetic phases have been predicted in twisted two-dimensional CrI due to competing ferromagnetic (FM) and antiferromagnetic (AFM) interl…
Tailored tunnel magnetoresistance response in three ultrathin chromium trihalides
Hyun Ho Kim, Bowen Yang, Shangjie Tian +4
Materials that demonstrate large magnetoresistance have attracted significant interest for many decades. Recently, extremely large tunnel magnetoresistance (TMR) has been reported…
Photoinduced Interlayer Dynamics in T-MoTe: A Broadband Pump-Probe Study
Meixin Cheng, Shazhou Zhong, Nicolas Rivas +9
We report on time-resolved broadband transient reflectivity (tr-bb-TR) measurements performed on a bulk single crystal of T-MoTe as a function of the incident pump fluence…
Photocurrent Imaging of Multi-Memristive Charge Density Wave Switching in Two-Dimensional 1T-TaS2
Tarun Patel, Junichi Okamoto, Tina Dekker +6
Transport studies of atomically thin 1T-TaS2 have demonstrated the presence of intermediate resistance states across the nearly commensurate (NC) to commensurate (C) charge density…
Tuning Coupled Toroidic and Polar Orders in a Bilayer Antiferromagnet
Chuangtang Wang, Xiaoyu Guo, Zixin Zhai +5
Magnetic toroidal order features a loop-like arrangement of magnetic dipole moments, thus breaking both spatial inversion (P) and time-reversal (T) symmetries while preserving thei…
Magneto-memristive switching in a two-dimensional layer antiferromagnet
Hyun Ho Kim, Shengwei Jiang, Bowen Yang +7
Memristive devices whose resistance can be hysteretically switched by electric field or current are intensely pursued both for fundamental interest as well as potential application…
Quantum tunneling devices incorporating two-dimensional magnetic semiconductors
Hyun Ho Kim, Adam W. Tsen
Research in two-dimensional (2D) materials has experienced rapid growth in the past few years. In particular, various layered compounds exhibiting quantum phenomena, such as superc…
Gate-Tunable Multi-Band van der Waals Photodetector and Polarization Sensor
Daozhi Shen, HeeBong Yang, Tarun Patel +5
A single photodetector with tunable detection wavelengths and polarization sensitivity can potentially be harnessed for diverse optical applications ranging from imaging and sensin…
Magnetic anisotropy reversal driven by structural symmetry-breaking in monolayer α-RuCl3
Bowen Yang, Yin Min Goh, Suk Hyun Sung +14
Layered α-RuCl3 is a promising material to potentially realize the long-sought Kitaev quantum spin liquid with fractionalized excitations. While evidence of this exotic state has…
High-Performance Mid-IR to Deep-UV van der Waals Photodetectors Capable of Local Spectroscopy at Room Temperature
Daozhi Shen, HeeBong Yang, Christian Spudat +13
The ability to perform broadband optical spectroscopy with sub-diffraction-limit resolution is highly sought-after for a wide range of critical applications. However, sophisticated…
Lessons from -RuCl3 for pursuing quantum spin liquid physics in atomically thin materials
Claudia Ojeda-Aristizabal, Xiaohu Zheng, Changsong Xu +20
Quantum spin liquids can arise from Kitaev magnetic interactions, and exhibit fractionalized excitations with the potential for a topological form of quantum computation. This revi…
Structural Monoclinicity and Its Coupling to Layered Magnetism in Few-Layer
Xiaoyu Guo, Wencan Jin, Zhipeng Ye +13
Using polarization-resolved Raman spectroscopy, we investigate layer number, temperature, and magnetic field dependence of Raman spectra in one- to four-layer . L…
Observation of the polaronic character of excitons in a two-dimensional semiconducting magnet
Wencan Jin, Hyun Ho Kim, Zhipeng Ye +15
Exciton dynamics can be strongly affected by lattice vibrations through electron-phonon coupling. This is rarely explored in two-dimensional magnetic semiconductors. Focusing on bi…
Dimensionality-driven orthorhombic MoTe2 at room temperature
Rui He, Shazhou Zhong, Hyun Ho Kim +9
We use a combination of Raman spectroscopy and transport measurements to study thin flakes of the type-II Weyl semimetal candidate MoTe2 protected from oxidation. In contrast to bu…
Semiconductor nanowire metamaterial for broadband near-unity absorption
Burak Tekcan, Brad van Kasteren, Sasan V. Grayli +6
The realization of a semiconductor near-unity absorber in the infrared will provide new capabilities to transform applications in sensing, health, imaging, and quantum information…
Tunable layered-magnetism-assisted magneto-Raman effect in a two-dimensional magnet
Wencan Jin, Zhipeng Ye, Xiangpeng Luo +13
We use a combination of polarized Raman spectroscopy experiment and model magnetism-phonon coupling calculations to study the rich magneto-Raman effect in the two-dimensional (2D)…
Atomic Lattice Disorder in Charge Density Wave Phases of Exfoliated Dichalcogenides (1T-TaS2)
Robert Hovden, Adam W. Tsen, Pengzi Liu +8
Charge density waves (CDW) and their concomitant periodic lattice distortions (PLD) govern the electronic properties in many layered transition-metal dichalcogenides. In particular…
Observation and manipulation of a phase separated state in a charge density wave material
Sean M. Walker, Tarun Patel, Junichi Okamoto +8
The 1T polytype of TaS has been studied extensively as a strongly correlated system. As 1T-TaS is thinned towards the 2D limit, its phase diagram shows si…
Evolution of interlayer and intralayer magnetism in three atomically thin chromium trihalides
Hyun Ho Kim, Bowen Yang, Siwen Li +16
We conduct a comprehensive study of three different magnetic semiconductors, CrI, CrBr, and CrCl, by incorporating both few- and bi-layer samples in van der Waals tunne…
Magnetic field-induced quantum phase transitions in a van der Waals magnet
Siwen Li, Zhipeng Ye, Xiangpeng Luo +10
Exploring new parameter regimes to realize and control novel phases of matter has been a main theme in modern condensed matter physics research. The recent discovery of 2D magnetis…
Strain Solitons and Topological Defects in Bilayer Graphene
Jonathan S. Alden, Adam W. Tsen, Pinshane Y. Huang +5
Spontaneous symmetry-breaking, where the ground state of a system has lower symmetry than the underlying Hamiltonian, is ubiquitous in physics. It leads to multiply-degenerate grou…
One million percent tunnel magnetoresistance in a magnetic van der Waals heterostructure
Hyun Ho Kim, Bowen Yang, Tarun Patel +5
We report the observation of a very large negative magnetoresistance effect in a van der Waals tunnel junction incorporating a thin magnetic semiconductor, CrI3, as the active laye…
Tuning Ising superconductivity with layer and spin-orbit coupling in two-dimensional transition-metal dichalcogenides
Sergio C. de la Barrera, Michael R. Sinko, Devashish P. Gopalan +8
Systems that simultaneously exhibit superconductivity and spin-orbit coupling are predicted to provide a route toward topological superconductivity and unconventional electron pair…
Giant -axis nonlinear anomalous Hall effect in T-MoTe and WTe
Archana Tiwari, Fangchu Chen, Shazhou Zhong +11
While the anomalous Hall effect can manifest even without an external magnetic field, time reversal symmetry is nonetheless still broken by the internal magnetization of the sample…
Distinct surface and bulk charge density waves in ultrathin 1T-TaS2
Rui He, Junichi Okamoto, Zhipeng Ye +10
We employ low-frequency Raman spectroscopy to study the nearly commensurate (NC) to commensurate (C) charge density wave (CDW) transition in 1T-TaS2 ultrathin flakes protected from…
Direct observation of distinct bulk and edge nonequilibrium spin accumulation in ultrathin MoTe
Fangchu Chen, Kamal Das, Bowen Yang +11
Low-symmetry two-dimensional (2D) topological materials such as MoTe host efficient charge-to-spin conversion (CSC) mechanisms that can be harnessed for novel electronic and sp…