arXiv subjects

Alpin N. Tatan

Publications and source records attributed to Alpin N. Tatan.

4 recordsLinked to original sources

arXiv2025

Exploring functionalized Zr$_2$N and Sc$_2$N MXenes as superconducting candidates with $\textit{ab initio}$ calculations

We study new superconductor candidates in functionalized MXenes Zr$_2$NS$_2$, Zr$_2$NCl$_2$, and Sc$_2$NCl$_2$ with $\textit{ab initio}$ calculations based on density functional theory for superconductors (SCDFT). The superconducting transition temperature $(T_c)$ at ambient pressure is predicted to reach 9.48 K (Zr$_2$NS$_2$), with potential further improvements under applied strain. We note that the changes in the profiles of superconducting gap $(Δ)$ and electron-phonon coupling $(λ)$ across the Fermi surface may be influenced by their modified electronic bandstructure components.

cond-mat.supr-con↗

arXiv2024

Magnetic phases of electron-doped infinite-layer Sr$_{1-x}$La$_x$CuO$_2$ from first-principles density functional calculations

The magnetic phases of electron-doped infinite-layer Sr$_{1-x}$La$_x$CuO$_2$ are elucidated by first-principles density functional calculations. The antiferromagnetic parent state, metallic transition, as well as lattice evolution with doping and pressure are found to be consistent with experiments. The specific heat coefficient $γ$, magnetic exchange coupling $J$, as well as the density of states at Fermi level $N(0)$ of low-energy states with multiple magnetic configurations are investigated. We highlight a subset of such states in which we note an increase in $N(0)$ to suggest the interesting effects of magnetic fluctuations and La substitution on the electronic structure of this material.

cond-mat.supr-con↗

arXiv2022

First-principles electronic structure investigation of HgBa$_{2}$Ca$_{n-1}$Cu$_{n}$O$_{2n+2+x}$ with the SCAN density functional

We perform first-principles calculation to study the electronic structure of HgBa$_{2}$Ca$_{n-1}$Cu$_{n}$O$_{2n+2+x}$ copper oxides up to $n = 6$ for the undoped parent compound $(x = 0)$ and up to $n = 3$ for the doped compound $(x > 0)$ by means of the SCAN meta-GGA density functional. Our calculations predict an antiferromagnetic insulator ground state for the parent compounds with an energy gap that decreases with the number of CuO$_{2}$ planes. We report structural, electronic and magnetic order evolution with $x$ which agree with experiments. We find an enhanced density of states at Fermi level at $x \approx 0.25$ for the single-layered compound manifesting in a peak of the Sommerfeld parameter, which recently has been discussed as a possible signature of quantum criticality generic to all cuprates.

cond-mat.str-el↗

arXiv2018

Electrons imitating light: Frustrated supercritical collapse in charged arrays on graphene

The photon-like electronic dispersion of graphene bestows its charge carriers with unusual confinement properties that depend strongly on the geometry and strength of the surrounding potential. Here we report bottom-up synthesis of atomically-precise one-dimensional (1D) arrays of point charges aimed at exploring supercritical confinement of carriers in graphene for new geometries. The arrays were synthesized by arranging F4TCNQ molecules into a 1D lattice on back-gated graphene devices, allowing precise tuning of both the molecular charge state and the array periodicity. Dilute arrays of ionized F4TCNQ molecules are seen to behave like isolated subcritical charges but dense arrays show emergent supercriticality. In contrast to compact supercritical clusters, extended 1D charge arrays exhibit both supercritical and subcritical characteristics and belong to a new physical regime termed frustrated supercritical collapse. Here carriers in the far-field are attracted by a supercritical charge distribution, but have their fall to the center frustrated by subcritical potentials in the near-field, similar to the trapping of light by a dense cluster of stars in general relativity.

cond-mat.mes-hall↗