Related papers: K. Alex M\"uller: Science between ferroelectricity…
Ferroelectricity and metallicity are usually believed not to coexist because conducting electrons would screen out static internal electric fields. In 1965, Anderson and Blount proposed the concept of 'ferroelectric metal', however, it is…
A pivotal challenge posed by unconventional superconductors is to unravel how superconductivity emerges upon cooling from the generally complex normal state. Some of the most prominent unconventional superconductors are oxides: strontium…
Extreme pressure strongly affects the superconducting properties of ``simple'' elemental metals, like Li, K and Al. Pressure induces superconductivity in Li (as high as 17 K), while suppressing it in Al. We report first-principles…
The vision of ``room temperature superconductivity'' has appeared intermittently but prominently in the literature since 1964, when W. A. Little and V. L. Ginzburg began working on the `problem of high temperature superconductivity' around…
Heusler alloys were discovered in 1903, and materials with half-metallic characteristics have drawn more attention from researchers since the advances in semiconductor industry. Heusler alloys have found application as spin-filters, tunnel…
We report on the first observation of a pronounced re-entrant superconductivity phenomenon in superconductor/ferromagnetic layered systems. The results were obtained using a superconductor/ferromagnetic-alloy bilayer of Nb/Cu(1-x)Ni(x). The…
In my short essay in honor of Karl-Alex Mueller, I would like to deal with some aspects that have been on my mind since the beginning of my own research. Some of the facts and questions mentioned here have been known or clarified for a long…
Results from dielectric and structural measurements on epitaxial SrTiO$_3$/BaZrO$_3$ superlattices reveal properties that cannot be explained simply in terms of those measured on single films of the constituent materials. For large…
Studies of the effect of high pressure on superconductivity began in 1925 with the seminal work of Sizoo and Onnes on Sn to 0.03 GPa and have continued up to the present day to pressures in the 200 - 300 GPa range. Such enormous pressures…
The superconducting state of the newly discovered superconductor K$_2$Cr$_3$As$_3$ with a quasi-one-dimensional crystal structure ($T_{\bf c}\sim$ 6 K) has been investigated by using magnetization and muon-spin relaxation or rotation…
The discovery of wurtzite ferroelectrics opens new frontiers in polar materials, yet their behavior at cryogenic temperatures remains unexplored. Here, we reveal unprecedented ferroelectric properties in ultrathin (10 nm)…
Ferroelectric switching is unambigiously demonstrated for the first time in a III-V semiconductor based material: AlScN -- A discovery which could help to satisfy the urgent demand for thin film ferroelectrics with high performance and good…
The famous Two-Temperature Model (TTM) used extensively in the investigations of energy relaxation in photo-excited systems originated in the seminal work of M. I. Kaganov, I. M. Lifshitz, and L. V. Tanatarov (KLT) in 1957. The idea that…
Superconductivity has been one of the focal points in medium and high-entropy alloys (MEAs-HEAs) since the first discovery of the HEA superconductor in 2014. Until now, most HEAs' superconducting transition temperature (Tc) has not exceeded…
The thermopower and thermal conductivity of superconducting perovskite $MgCNi_3$ ($T_c \approx$ 8 K) have been studied. The thermopower is negative from room temperature to 10 K. Combining with the negative Hall coefficient reported…
Since the discovery of high-temperature superconductivity (SC) in quasi-two-dimensional copper oxides, a few layered compounds, which bear similarities to the cuprates, have also been found to host unconventional SC. Our recent observation…
Superconductivity was recently observed in the iron-arsenic-based compounds with a superconducting transition temperature (Tc) as high as 56K [1-7], naturally raising comparisons with the high Tc copper oxides. The copper oxides have…
The search for superconductivity with higher transition temperature ($T_C$) has long been a challenge in research efforts ever since its first discovery in 1911. The effort has led to the discovery of various kinds of superconductors and…
This survey provides a brief account for the start of organic superconductivity motivated by the quest for high Tc superconductors and its development since the eighties'. Besides superconductivity found in 1D organics in 1980, progresses…
Despite intense efforts during the last 25 years, the physics of unconventional superconductors, including the cuprates with a very high transition temperature, is still a controversial subject. It is believed that superconductivity in many…