Publications
Superfluid helium-3 in confined quarters
Liquid helium-3 and helium-4 are remarkable substances. They are quantum liquids, meaning that their behavior is governed by the laws of quantum mechanics. Because of their small atomic mass, each isotope exists in a liquid state down to the temperature of absolute zero. And at sufficiently low temperature, each becomes a superfluid. However, the two isotopes have very different properties because 3He is a fermion and 4He is a boson. As a result of their different statistics, superfluidity in 3He appears at a temperature one-thousandth of that at which superfluid 4He forms.
Coherent Superconductivity with a Large Gap Ratio from Incoherent Metals
A mysterious incoherent metallic (IM) normal state with T-linear resistivity is ubiquitous among strongly correlated superconductors. Recent progress with microscopic models exhibiting IM transport has presented the opportunity for us to study new models that exhibit direct transitions into a superconducting state out of IM states within the framework of connected Sachdev-Ye-Kitaev "quantum dots." Here, local Sachdev-Ye-Kitaev interactions within a dot produce IM transport in the normal state, while local attractive interactions drive superconductivity.
MoS2 monolayers on Si and SiO2 nanocone arrays: Influences of 3D dielectric material refractive index on 2D MoS2 optical absorption
Heterostructures enable the control of transport and recombination of charge carriers, which are either injected through electrodes, or created by light illumination. Instead of full 2D-material-heterostructures in device applications, using hybrid heterostructures consisting of 2D and 3D materials is an alternative approach to take advantage of the unique physical properties of 2D materials. In addition, 3D dielectric nanostructures exhibit useful optical properties such as broadband omnidirectional antireflection effects and strongly concentrated light near the surface.
Engineering Carrier Effective Masses in Ultrathin Quantum Wells of IrO2
The carrier effective mass plays a crucial role in modern electronic, optical, and catalytic devices and is fundamentally related to key properties of solids such as the mobility and density of states. Here we demonstrate a method to deterministically engineer the effective mass using spatial confinement in metallic quantum wells of the transition metal oxide IrO2.
WNT signaling memory is required for ACTIVIN to function as a morphogen in human gastruloids
Self-organization of discrete fates in human gastruloids is mediated by a hierarchy of signaling pathways. How these pathways are integrated in time, and whether cells maintain a memory of their signaling history remains obscure. Here, we dissect the temporal integration of two key pathways, WNT and ACTIVIN, which along with BMP control gastrulation.
Candidate theory for the strange metal phase at a finite-energy window
We propose a lattice model for strongly interacting electrons with the potential to explain the main phenomenology of the strange metal phase in the cuprate high-temperature superconductors. Our model is motivated by the recently developed "tetrahedron" rank-3 tensor model that mimics much of the physics of the better-known Sachdev-Ye-Kitaev (SYK) model. Our electron model has the following advantageous properties: (1) it needs only one orbital per site on the square lattice. (2) It does not require any quenched random interaction.
Ultrafast manipulation of mirror domain walls in a charge density wave
Topological defects, potential information carriers, were written into and erased from a solid with femtosecond light pulses. , Domain walls (DWs) are singularities in an ordered medium that often host exotic phenomena such as charge ordering, insulator-metal transition, or superconductivity. The ability to locally write and erase DWs is highly desirable, as it allows one to design material functionality by patterning DWs in specific configurations.
Canonical sectors and evolution of firms in the US stock markets
Unsupervised machine learning can provide an objective and comprehensive broad-level sector decomposition of stocks. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
Irrelevance of magnetic proximity effect to spin-orbit torques in heavy-metal/ferromagnet bilayers
The magnetic proximity effect (MPE) is a well-established magnetic phenomenon that occurs at certain heavy-metal (HM)/ferromagnet (FM) interfaces. However, there is still an active debate as to whether the presence of a MPE affects spin transport through such a HM/FM interface. Here we demonstrate that the MPE at Pt/Co and Au0.25Pt0.75/Co interfaces can be enhanced substantially by thermal annealing protocols.
Pomeranchuk Instability of Composite Fermi Liquids
Nematicity in quantum Hall systems has been experimentally well established at excited Landau levels. The mechanism of the symmetry breaking, however, is still unknown. Pomeranchuk instability of Fermi liquid parameter F≤-1 in the angular momentum =2 channel has been argued to be the relevant mechanism, yet there are no definitive theoretical proofs. Here we calculate, using the variational Monte Carlo technique, Fermi liquid parameters F of the composite fermion Fermi liquid with a finite layer width.